Guidance

Management of acute respiratory infection outbreaks in care homes guidance

Updated 24 July 2024

Main messages

Outbreaks of acute respiratory infection (ARI) can have significant morbidity and mortality. Residents of care homes for older adults are particularly vulnerable to severe outcomes. Some residents of care homes for younger adults with physical disabilities or other health conditions may also be at enhanced risk.

Proportionate, risk-based and time limited interventions are required to protect health, social and emotional wellbeing of residents.

Neuraminidase inhibitors (antivirals) demonstrably reduce transmission in influenza outbreaks and can prevent hospitalisations in case-patients. They are therefore recommended for deployment through NHS commissioned pathways in line with assessment by health protection teams (HPTs), for prophylaxis as well as treatment.

It is important that care home residents eligible for COVID-19 treatments are able to access these promptly.

What has changed

This guidance replaces the Public Health England (PHE) 2020 Guidelines for PHE HPTs on the management of outbreaks of influenza-like illness (ILI) in care homes.

This version includes more details on viruses other than influenza and SARS-CoV-2 and takes into account changes in COVID-19 (SARS-CoV-2) epidemiology and associated recommendations on outbreak control.

Definitions including the window for outbreak detection and the information to be collected from a care home have also been updated.

Who this guidance is for

This guidance provides information and advice for health protection practitioners and community infection prevention and control professionals, based in local authorities or in the NHS who have similar responsibilities, and for HPTs in the devolved administrations; when requested to advise on the management of suspected viral ARI outbreaks in Care Quality Commission (CQC) registered care homes for adults in England. 

The guidance includes information on:

• risk assessment
• surveillance
• routine infection prevention control (IPC)
• outbreak management
• antiviral treatment and prophylaxis

Care homes vary substantially in size and their resident populations. Residents in care homes for older adults are generally at the highest risk of severe outcomes. Care homes for adults with learning disability are typically much smaller, and household-like by design. They may be similar to Enhanced Care or Supported living settings, other than commissioning arrangements.    

Management of suspected bacterial pneumonia clusters is out of scope (other than in their association with suspected underlying respiratory virus outbreaks).

For queries relating to this document, please contact:
[email protected]

Background

Influenza, COVID-19 and other respiratory infections are a major cause of hospitalisation, morbidity and death among older adults. Underlying chronic health conditions make care home residents both more susceptible and vulnerable to severe disease, and hospitalisation rates during ARI outbreaks can be high (1 and 2). Respiratory infections may also spread rapidly in care homes, in the absence of control measures, resulting in high attack rates due to prolonged close contact between residents, and between residents and their carers.

It is anticipated that COVID-19, influenza and other respiratory illnesses will need to be investigated and managed simultaneously. Co-infection of 2 pathogens in a case and co-occurrence or co-circulation in a setting may occur.

The most identified causes of outbreaks of ARI in care homes, other than SARS-CoV-2, are influenza viruses and non-influenza viruses such as:

• respiratory syncytial virus (RSV)
• rhinovirus
• adenovirus
• parainfluenza
• human metapneumovirus (hMPV)

While SARS-CoV-2 does not yet have an established seasonality, these other viruses tend to be seasonal, peaking between autumn and spring, although not necessarily at the same time. For example, while the incidence of RSV diagnosis is typically highest around late December, influenza activity can peak any time between December and February, and the intensity and dominant strain varies by season. In addition, sporadic outbreaks can occur throughout the year. In particular, influenza outbreaks in care homes may occur early in the autumn before seasonal immunisation campaigns have been fully implemented and before any increased influenza activity is detected in the wider community, or late in spring when influenza activity in the rest of the community has declined.

Changes in social contact rates due to the COVID-19 pandemic have caused some changes to typical seasonal patterns of some respiratory viruses and this should be taken into consideration in epidemiological risk assessments.

Some acute respiratory virus diseases have specific pharmaceutical interventions deployable during an outbreak such as antivirals for influenza treatment and prophylaxis, or therapeutics for COVID-19.

Vaccination of care home residents and staff against COVID-19 and seasonal influenza is extremely important in limiting the risk from outbreaks, particularly reducing the risk of severe infection (3). Influenza vaccine effectiveness varies by year and by subtype or strain, and tends to be generally lower among care home residents (due to their age profile and associated reduced immune responses to vaccination), therefore influenza outbreaks may still occur despite good vaccine uptake (4).

Epidemiology of ARI viruses

Transmission routes

Respiratory viruses are transmitted primarily through droplet transmission when in close contact (proximity) or through direct interpersonal contact (touch). Transmission can also occur through aerosols and through indirect contact, with some evidence suggesting that respiratory viruses may remain on inanimate surfaces for several hours.

Infection control precautions are therefore based on limiting and avoiding transmission from contact, aerosol and droplet routes, as well as environmental cleaning.

Presentation

These may all have similar symptoms including:

• runny nose
• sore throat
• cough
• wheeze
• sometimes lethargy, body aches and fever

See symptoms detail in the definitions section below, and symptoms or signs that may be more or less common for specific pathogens.

Incubation periods vary between cases and viruses but are usually between 12 hours and 5 days. This may extend up to 8 days for COVID-19 and RSV and has been reported as long as 14 days for adenovirus. Incubation periods are not symmetrical but right-skewed (positive skew), meaning most onset occurs in the first half of the stated windows. While the original ‘Wuhan’ strain of SARS-CoV-2 had an incubation period of up to 14 days, for Omicron-era variants, incubation periods are median 3 to 4 days, range 0 to 8 days.

Infectious periods also vary but often begin at symptom onset or within the 12 to 24 hours prior to symptom onset and usually extend for around 5 days afterwards.

Influenza

The median incubation period of influenza A is slightly under 2 full days and ranges from less than 1 day to 3 to 4 days. The influenza B median and range may be shorter (5).

For influenza there is limited evidence of presymptomatic transmission (6). Operationally, the period of infectiousness (that is, communicability) should ordinarily be considered as starting with the onset of influenza-like illness (ILI) symptoms and lasts for the duration of symptoms.

Evidence also shows that viral shedding following influenza infection can be prolonged among some older people, and among people with chronic long-term medical conditions and individuals on immunosuppressive therapy (7 and 8) .

Other risk factors for prolonged shedding are:

• older age
• influenza antiviral treatment was started more than 48 hours after symptom onset
• case did not receive influenza antiviral treatment
• case has persistent respiratory symptoms after 5 days of influenza antiviral treatment
• case was diagnosed with pneumonia
• case has an impaired immune system from conditions including systemic corticosteroid use, immunosuppressive/immunomodulating biological therapy, chemotherapy, organ or bone marrow transplantation, or advanced HIV/AIDS infection
• case has other major medical conditions (including malignancy, chronic lung disease, renal disease, heart disease, liver disease, stroke)

This has implications for outbreak measures, described below.

During an influenza season, the dominant circulating strain may vary and could be replaced by a second strain later in the same season. Therefore, while it is infrequent for a care home community to experience a second laboratory confirmed outbreak, there could be additional outbreaks in the same season, if:

• a distinct, second strain becomes the dominant circulating strain, or
• sufficient numbers of members the care home community have changed

Testing, which includes typing and ideally subtyping, can support decision making. In the event of a second outbreak being identified prior to laboratory confirmation being available, the likelihood of seasonal influenza should be considered within the context of national influenza surveillance data to inform decision making.

Adenovirus

Infections commonly affect the respiratory system and may cause cold-like symptoms, sore throat, bronchitis and pneumonia. Adenoviruses can also cause other illnesses including gastroenteritis and are an important cause of conjunctivitis. Occurrence is year-round but activity may be higher mid-late winter into spring.

Limited data suggests the incubation period for adenovirus respiratory infection ranges from 2 to 14 days and symptoms typically last 3 to 5 days. 

Adenovirus can have a low infectious dose. It can be spread from respiratory, faecal and fomite routes. Presentations may be more severe and infectious periods longer in immunocompromised people.

There are few reports of adenovirus ARI outbreaks in adult long term care facilities (9).

Human metapneumovirus

hMPV is a relatively recently discovered respiratory virus (10). It is associated with a range of respiratory illnesses in young children and older adults including lower respiratory tract infection (LRTI) and pneumonia.

Cough is very common, fever, coryza and LRTI signs may also be prevalent in outbreaks.

Swab-positivity surveillance suggests infection is more common in early childhood than older age groups; though may be influenced by clinical manifestation and presentation to healthcare services, other data suggest reinfection is common throughout the life course (11). Activity is higher between autumn and spring, peaking in winter.

hPMV is transmitted by droplets and by secretions from close contact with an infected person or contaminated objects and surfaces, including hands. The incubation period is reported as 3 to 6 days.

There are few reports of hMPV outbreaks in long term care facilities. Those available in the literature commonly note fatal cases occurring. One outbreak report (12) noted a 50% attack rate with median duration of illness of 7 days and 13% of residents requiring hospitalisation. A study of 2 outbreaks found median illness durations of 4.5 and 21 days.

Parainfluenza

Human parainfluenza virus (PIV) types 1 to 4 cause upper and LRTI in young children, the elderly and the immunocompromised. Re-infections can arise throughout life, though ARI requiring medical care is much less frequent in adults than in young children.

PIV1 and PIV2 both cause croup (a barking cough in children), with PIV1 most often identified as the cause. Both can also cause upper and lower respiratory illness, and cold-like symptoms. PIV3 is more often associated with bronchiolitis (in children), bronchitis, and pneumonia. PIV4 is less commonly recognised but may cause mild to severe respiratory illnesses. PIV may present with hoarseness in adults amongst common ARI symptoms.

PIV in older adults may cause exacerbation of underlying conditions such as chronic obstructive pulmonary disease (COPD) and heart failure (13). PIV infections including primary pneumonia may also be complicated by bacterial pneumonia in care home outbreaks (14).

Parainfluenza is detected throughout the year, with peaks in spring and autumn. Swab positivity of patients in UKHSA DataMart surveillance indicates relatively low prevalence.

Literature estimates indicate an incubation period of 2-6 days, suggesting 25% of cases arise within 2.1 days and 75% of cases arise within 3.2 days (15).

The exact period of communicability is not known. However, PIV3 (the most infective PIV) is known to shed from the oropharynx for about 3 to 10 days during initial infection. Shedding rates are lower for subsequent infections.

There are few reports in the literature of outbreaks of PIV in care homes for adults. PIV clustering has been observed (16), compatible with transmission between neighbouring residents in a large facility, as well as more widespread transmission with fatal cases in a report (17) from a medium-sized establishment.

Respiratory syncytial virus

Respiratory syncytial virus (RSV) is an important cause of LRTI in older adults and is associated with exacerbation of COPD and chronic heart disease. Infection may also be more severe in immunocompromised people. Most people are infected before the age of 2 years and repeat infections are common throughout life due to partial immunity. RSV hospitalisations are associated with high mortality in older adults. RSV activity typically increases from October, and declines in February. Cough is very common, and the presence of wheezing may help clinically differentiate from other infections.

There are few reports in the scientific literature of RSV care home outbreaks, though outbreaks are seen by HPTs in annual epidemic periods. Attack rates can be high (18, 19 and 20). Outbreak severity can be mild (21) particularly if contained (22). High attack rate outbreaks are often associated with severe episodes and fatalities.

Rhinovirus

Rhinovirus is the most frequent cause of the common cold. It can also be associated with LRTI in those with underlying respiratory disease and the immunocompromised.

Rhinovirus has an average incubation period of 2 days (5). Infectiousness is considered to end with resolution of acute symptoms.

Few care home outbreaks are described in the scientific literature. In care home outbreaks with high attack rates, fatal cases may arise (23).

SARS-CoV-2 (COVID-19)

SARS-CoV-2 is a respiratory virus that causes the COVID-19 disease, first detected in Wuhan, China in 2019 (24). Common symptoms include cough, fever, headache, and fatigue. Early variants in the first and second waves of COVID-19 in 2020 and early 2021 were associated with markedly higher mortality in older ages, with extensive care home outbreaks having high attack rates and high mortality. Outbreaks in the vaccination era have typically been much less severe.

Compared to earlier variants, the Omicron variant, which became dominant in the UK in December 2021, is less likely (25) to cause loss of smell (anosmia) and taste (ageusia). Severe cases can lead to pneumonia, acute respiratory distress syndrome, multiple organ failure and death.

The long-term sequalae of COVID-19 is known as post-acute sequalae of COVID-19 (PASC), or more commonly, long COVID-19. This is defined as signs and symptoms lasting 12 or more weeks are seen in 4.5% of cases affecting both mental and physical health and including almost all organ systems.

Spread is primarily via respiratory droplets and aerosols, with fomites thought to play a minor role in transmission (26). The incubation period and infectious period for COVID-19/SARS-CoV-2 has shortened as with more recent variants, with the incubation period for the Omicron variant thought to be 3 to 4 days, with peak infectivity thought to occur around day 3 of illness.

Currently COVID-19 does not follow a true seasonal pattern. While increases in cases and outbreaks are seen during winter, there is a baseline of cases all year round, with additional waves of increased case numbers approximately every 4 months.

Seasonal coronavirus

Common human coronaviruses, including types 229E, NL63, OC43, and HKU1 primarily infect the upper respiratory and gastrointestinal tract and are believed to cause a significant proportion of common colds in human adults. Occasionally, coronaviruses can cause more significant LRTIs in humans with pneumonia. This is more likely in immunocompromised individuals, people with cardiopulmonary illnesses, elderly people and young children.

Analysis suggests incubation periods have a 2 to 5 day range, median 3 days (15).

Limited data are available on the duration of shedding of coronavirus. A study of household transmission of seasonal coronaviruses suggests most transmission occurs within a day of onset of symptoms (18).

There are very few scientific reports of seasonal coronavirus outbreaks in care homes.

Case definitions

ARI

The UKHSA ARI case definition for use in care homes is acute onset of one or more of the above respiratory symptoms and a clinician’s judgement that the illness is due to an ARI.

Influenza-like illness

The UKHSA ILI case definition for use in care homes is as follows:

(i) oral or tympanic temperature of at least 37.8°C, and acute onset of at least one of the following respiratory symptoms:

• cough (with or without sputum)
• sore throat
• coryza (nasal discharge or congestion)
• dyspnea (shortness of breath)
• hoarseness
• sneezing
• wheezing

Or alternatively

(ii) an acute deterioration in physical or mental ability without other known cause

The UKHSA definition of ILI in care home residents maintains a degree of specificity to support public health action within the care home setting by including a raised temperature of 37.8°C or higher. However, be aware that over 40% of older persons with influenza will not develop a fever of this magnitude (28).

Note that antipyretic analgesics such as paracetamol may suppress fever (also a consideration in assessing resolution of acute symptoms).

Fever is used to define ILI by both the World Health Organization (acute respiratory infection with fever of at least 38.0°C and cough) and the US Centers for Disease Control and Prevention (fever of at least 37.8°C with a cough or a sore throat or both). The UKHSA case definition is consistent with these approaches.

Confirmed influenza

A laboratory or point of care test detection of influenza.

Testing should usually be carried out in someone who currently has symptoms (as per the ARI or ILI definitions above) rather than in someone who is asymptomatic. However, detections in asymptomatic people should also be considered when undertaking a risk assessment.

Confirmed COVID-19

A laboratory or point of care test detection of SARS-CoV-2.

Testing should usually be carried out in someone who currently has symptoms (as per the ARI or ILI definitions above) rather than in someone who is asymptomatic. However, detections in asymptomatic people should also be considered when undertaking a risk assessment.

Probable cases and confirmed cases of other respiratory virus diseases

Positive results for other respiratory viruses should similarly be used to classify cases as confirmed, based on detection by a suitably specific assay such as polymerase chain reaction (PCR) or well-characterised point of care test.

ARI cases arising in a probable or confirmed outbreak, or epidemiologically-linked to a confirmed case, should be considered as probable cases of the same disease if there is no contradictory virological test finding.

Outbreak definitions

ARI outbreak

An outbreak of an ARI is defined as 2 or more ARI or ILI cases in epidemiologically-linked residents.    

A 5-day window for case onset can be used as a pragmatic window for determining if there is an outbreak, noting that incubation and infectious periods can vary between respiratory viruses (see epidemiology section).

Atypical, subclinical, or otherwise undetected cases can arise within chains of transmission. Conversely, multiple introductions of the same or different pathogens to a home are possible, resulting in a cluster of acute respiratory disease that is not an outbreak.

Respiratory panel testing, such as multiplex PCR, is recommended for all ARI outbreaks where the pathogen is unknown and there are public health concerns, such as potential influenza antiviral intervention.

Care homes should inform the HPT (or other local partner) of a suspected outbreak in a timely manner. Care homes may on occasions seek advice on other situations, such as one resident plus one or more staff member with recent attendance and epidemiological indicators of possible transmission. HPTs should apply judgement as to whether this constitutes and outbreak and manage accordingly.

Influenza outbreak

Probable influenza outbreak

An ARI outbreak should be considered probable influenza if either:

(i) There is one case of confirmed influenza and there is no contradictory virological evidence from other symptomatic residents (such as positive COVID-19 lateral flow device (LFD) tests, although co-circulation and co-infection are possible); the plausibility of route of transmission within the home should be considered.

Or

(ii) In the judgement of a consultant in health protection or other senior HPT member, an ARI outbreak without influenza testing is likely to be caused by influenza. This may be supported by the presence of cases of ILI (not just ARI), local or national epidemiological indicators of influenza circulation, epidemiological links to other known cases, and no contradictory virological evidence on testing (such as positive COVID-19 LFD tests, although co-circulation and co-infection are possible).

Confirmed influenza outbreak

At least 2 confirmed cases of influenza in an ARI outbreak.  

The possibility of dual outbreaks (for example influenza and another pathogen) should also be considered.

COVID-19 outbreak

Probable COVID-19 outbreak

An ARI outbreak should be considered probable COVID-19 if either:

(i) There is one case of confirmed COVID-19 and there is no contradictory virological evidence from other symptomatic residents, with plausible routes of transmission within the home.

Or

(ii) In the judgement of a consultant in health protection or other senior health protection team member, an ARI outbreak without COVID-19 testing is likely to be caused by SARS-CoV-2. This may be supported by local or national epidemiological indicators of SARS-CoV-2 circulation, epidemiological links to other known cases, and no contradictory virological evidence on testing.

Again, note the possibility of co-circulation and co-infection.

Confirmed COVID-19 outbreak

At least 2 confirmed cases of COVID-19 in an ARI outbreak. 

The possibility of dual outbreaks (for example SARS-CoV-2 and another pathogen) should also be considered.

Investigation and surveillance

Risk assessment

When an ARI outbreak is initially notified to a UKHSA HPT, a range of information (see below) will be required to inform a local risk assessment. This will help assess the likelihood of influenza and COVID-19 (SARS-CoV-2) infection, assess the severity and extent of the outbreak, and guide control measures, such as partial or full closure of the care home to new admissions and options for restrictions on movement and supporting cases to stay away from others.

The checklist is not intended as a set of questions to be worked through line-by-line, unless being used as part of a toolkit to be completed by the care home, such as using the Care Outbreak Risk Assessment (OBRA) tool. For telephone reports of outbreaks, it is recommended to gather the information in a narrative or conversational format, referring to the checklist to ensure all necessary information has been gathered.

Equivalent local checklists may be employed, including by community IPC teams where this is the local arrangement.

Information to be collected in the event of an outbreak

There are a range of settings that have similarities to care homes, and the approach to information gathering at the time of reporting should be similar. However, it is important to note that options for management, including eligibility for outbreak testing, may differ.

Information about the care home

The care home will be asked to share information about the type of care home, including:

• type of care home or, if not a care home, the setting:
  • nursing care, residential care, mixed residential and nursing care
  • supported living or other extra care, including non-residential (day care, domiciliary care (home care), retirement home or village, or sheltered housing)
• size of the care home (total number of staff, total number of residents, bed capacity, number of empty beds)
• layout of the care home (for example distinct sub-units within the home such as floors) and any co-location with other services such as day care or intermediate care
• current number of residents in care setting
• total number of residents who are eligible for COVID-19 treatment if COVID-19 (SARS-CoV-2) is a possibility or confirmed
• total number of staff employed by the setting or who visit on a regular basis if not directly employed
• total number of staff in clinical risk groups for flu (if flu suspected or confirmed)
• details of GP practices associated with the home
• registered GPs of symptomatic residents and potentially exposed residents
• specific risk factors, for example dementia (including people who walk with purpose), challenging behaviour, immunocompromised

Characteristics of the outbreak

The care home will be asked to share information about the characteristics of the outbreak, including:

• total number of residents with symptoms
• total number of staff members with symptoms
• onset date of symptoms for first case
• onset date of symptoms for most reported recent case
• nature of the symptoms
• for how many residents or clients you have had to request GP review because of the severity of their symptoms
• number hospitalisations and intensive care unit (ICU) admissions (if so, which hospital and when?)
• number of deaths (and if the deaths were in hospitalised residents or at the care home)
• vaccination history of anyone hospitalised or who died because of COVID-19 or influenza
• influenza and COVID-19 vaccine uptake (%) among residents and staff members

Results of any recent testing

The care home will be asked to share information about the results of any recent tests undertaken, including:

• any results from virological or bacterial testing
• number of virologically confirmed cases (and the location of cases within the home if residents, or the work activities and work locations of staff cases), if any, or any negative test results

Outbreak control measures

The care home will be asked to share information about any outbreak control measures that have been introduced, including:

• current standard IPC measures and any additional outbreak measures introduced
• any issues with supporting cases to reduce contact with others (or other IPC measures, including personal protective equipment (PPE))
• whether antivirals or other pathogen specific treatments (for example COVID-19 therapeutics) have been provided for treatment or prophylaxis
• additional pressures, for example expected admissions from hospital, staffing

The care home will also be asked to share an epidemiological assessment of association between cases and the possibility of transmission in the home, which should include consideration of:

• geographical and social connectedness between cases (such as location of the resident cases and organisation of the home into different areas, arrangements for mealtimes and friendships or visiting between cases)
• the networks of staff that provide care for the cases, as an infected member of staff (including agency or bank, catering and cleaning members as well as care staff) could have infected multiple residents
• plausible or typical incubation and infectious periods or serial intervals for possible or confirmed pathogens
• the possibility of multiple introductions of the same or different pathogens (for example from visitors or staff) giving the impression of an outbreak in the home
• the possibility of missed asymptomatic or atypical cases in assessing possible chains of infection

The Infection prevention and control (IPC) in adult social care: acute respiratory infection (ARI) contains information for care homes on how residents and staff who have tested positive for COVID-19 should be managed. Community COVID-19 cases should be managed in line with the latest NHS guidance and pathways for Covid19 treatments.

In smaller household style care homes for residents who go out into the community, usually for younger adults, it may be less straightforward to understand whether there is an outbreak, as both residents and staff have community exposures.

A risk assessment should include consideration of the epidemiological assessment and the information gathered above, including:

• the number of residents and staff affected, their locations within the home and the attack rate (proportion who have become ill to date, per area if applicable)
• whether symptomatic residents can be effectively supported to stay away from others
• cohorting arrangements for residents and staff
• staffing levels
• availability of PPE
• the ability of the home to comply with all required IPC measures

Testing

Approaches to rapid testing

In an outbreak of ARI, rapid turnaround diagnostic virological testing of symptomatic cases is important in guiding outbreak control measures. Virological testing can include LFD tests used at the point of care, laboratory PCR tests and molecular point of care tests (mPOCTs).

If an ARI outbreak is suspected in line with above case and outbreak definitions, prompt LFD tests should be carried out for any symptomatic residents who are eligible for COVID-19 treatments. If results are negative it is recommended to arrange laboratory testing for influenza and other respiratory viruses in order to assess potential other viral causes of the outbreak. Suspected cases where individuals initially test negative, but still have symptoms of COVID-19, should do a total of 3 LFD tests over 3 days. Further guidance on treatments for COVID-19 is available.

During periods of low or uncertain influenza prevalence, influenza antivirals should usually only be initiated following virological confirmation. See also the section below on periods of influenza circulation.

An HPT audit of influenza outbreaks found that it was common for outbreaks to be initially diagnosed as ‘chest infection’ or ‘bacterial pneumonia’ outbreaks on primary care clinical assessment, where the underlying aetiology was subsequently identified as influenza on PCR. Early testing can support appropriate outbreak management.

Prompt use of LFD tests on eligible residents can help determine whether laboratory multiplex PCR is required. For example, if no samples are positive for SARS-CoV-2 on LFD having tested a reasonable number of patients (see below), the utility of PCR is higher.

Multiplex LFD testing (for example COVID 19, influenza A or B and RSV) can also be considered if suitably quality-assured products are readily available, though these are not commonly available at the time of writing. Sites may also be participating in piloting of multiplex-LFDs and findings should be interpreted in line with any guidance from pilot study investigators.

In some areas, mPOCT may also be available for one or multiple respiratory viruses. Local protocols should be followed for their use.

If initial tests (for example COVID-19 LFD, POCT) are not available, and cannot be obtained quickly (such as within 3 hours), or their results do not provide sufficient information to determine appropriate outbreak measures or antiviral use, further testing may be required. This should typically be a wider respiratory panel PCR test carried out at a UKHSA public health laboratory. Laboratory testing is recommended for influenza A and B, SARS-CoV-2 and RSV as a minimum, and is also recommended to include PIV, hMPV, rhinovirus, and adenovirus.

In the context of POCTs, laboratory testing (which includes influenza typing and, in particular influenza A subtyping) can add additional information to a risk assessment and important information for surveillance and vaccine effectiveness. Use of POCT may therefore require taking 2 swabs from one individual. In some localities, arrangements for postal swabbing kits have been successfully implemented in conjunction with the local public health laboratory to address this need. See consideration of results section below and surveillance section below.

Testing during periods when influenza is circulating in the community

During the Chief Medical Officer (CMO) declared ‘flu season’ (that is, when the Department of Health and Social Care has notified general medical practitioners that the influenza virus is circulating in the community), or (less commonly) outside this period if there is known to be circulation of influenza in the local area, empirical initiation of antivirals should be considered without laboratory confirmation based upon a risk assessment. The risk assessment should be carried out by the HPT in liaison with the care home, community IPC nurses or the relevant GP(s) to ascertain the likelihood of the outbreak being due to influenza.

Influenza or multi-pathogen testing is recommended where antivirals have been initiated empirically.

Factors to consider around empirical influenza antiviral use include:

• symptoms (indicative of ILI cases)
• national and local surveillance data on influenza and COVID-19
• recent COVID-19 test results
• influenza and COVID-19 vaccination uptake in staff and residents (although it is known that flu vaccine is less effective in the elderly and COVID-19 vaccination may have modest effectiveness against infection compared to severe disease)
• any information on vaccine match to circulating strains (primarily a consideration for influenza)

See also the UKHSA influenza antiviral guidance and guidance on COVID-19 treatments for advice on the use of testing for COVID-19 and influenza to inform antiviral prescribing.

Selection of cases for testing

Around 5 residents with the most recent symptom onset or otherwise considered most likely to yield a positive result for a respiratory virus on PCR should be tested. In practice, at the time of outbreak notification there are often relatively small numbers of symptomatic cases likely to yield informative results.

For scenarios where a home is divided into distinct operational units with multiple cases in each area, where independent concurrent outbreaks may have arisen, adequate testing numbers should be done for each area where feasible.

Staff should not ordinarily be among cases prioritised for outbreak risk assessment testing. Symptomatic staff are recommended to not work until they have recovered from acute symptoms. They should not be on-site and will therefore be less available for testing. Staff may also have different pathogen exposure and infection (for example from household members) and so their results may be less informative than those from resident swabbing.

Once the cause of the outbreak is established, new symptomatic cases may arise.  Decisions on whether to test these individuals should take into consideration whether a test result is likely to change the management of the outbreak, for example if a second pathogen is suspected in a prolonged outbreak. From a public health perspective, it is not routine to undertake additional testing in an established outbreak. Testing may be done as part of clinical diagnosis for the clinical management of individual patients for example to enable a prompt access to COVID-19 treatments for those eligible.

Further advice on operationalisation of testing during outbreaks may be contained in local HPT standard operating procedures or sought from the regional public health laboratory.

HPTs should work with local system partners to operationalise testing for COVID-19 (SARS-CoV-2), influenza and other respiratory viruses through local swabbing service partners, including UKHSA regional laboratories.

Consideration of test results

There may be simultaneous occurrence or circulation of more than one pathogen (such as SARS-CoV-2 and influenza) within a single care home outbreak.

Positive results for seasonal influenza (with or without SARS-CoV-2)

Detection of seasonal influenza, with or without the detection of other respiratory viruses, supports the prompt use of antivirals in accordance with the antiviral advice section.

Results should be further scrutinised to determine if seasonal influenza is limited to a specific area or part of the care home, such as a single unit or floor. This would inform the targeted use of antivirals.

Typing and subtyping results such as from a PCR at a regional UKHSA public health laboratory can also support risk assessment.

Influenza A(H3N2) ordinarily carries a greater risk of severe infection to current cohorts of older adults than influenza A(H1N1)pdm09, and also more than that for influenza B. Influenza A(H3N2) will also in general have the lowest vaccine effectiveness of these seasonal influenza (sub)types.

Subtyping findings can be used in combination with information on whether there is antigenically significant difference between strains in the vaccine and those in circulation.

Positive results for SARS-CoV-2

The Infection prevention and control (IPC) in adult social care: acute respiratory infection (ARI) guidance contains information for care homes on how residents and staff who have tested positive for COVID-19 should be managed. Community COVID-19 cases should be managed in line with the latest NHS guidance and pathways for Covid-19 treatments.

Co-infection with ARI and a bacterial pathogen

Detection of seasonal influenza with bacterial pathogens such as Streptococcus pneumoniae may prompt additional laboratory investigations and interventions (for example antibiotic use). This is of particular concern if there is a suggestion of invasive secondary bacterial infections. Consultants in UKHSA HPTs may wish to discuss these situations with specialists within the UKHSA Clinical and Emerging Infections directorate. See guidance on managing clusters of pneumococcal disease in closed settings.

Negative results for seasonal influenza

If seasonal influenza has not been detected on testing, then cessation of previously prescribed antivirals may be considered. Factors supporting this include:

• an adequate number of appropriately taken respiratory specimens from recent cases (within 5 days of onset of illness) and including any cases with ILI have been tested (typically around 5, and potentially more, if the care home is divided into self-contained units, with separation of residents and staff)
• all respiratory testing results have been received
• other respiratory pathogens have been detected which are consistent with the case presentations observed in the outbreak

Respiratory outbreak control measures

General respiratory outbreak control measures should be used for control all suspected viral ARI outbreaks. Consideration can be given for the use of virological testing to determine the appropriate control measures, noting that viruses which may be mild in the general population, such as RSV, can be severe and life-threatening for care home residents and that severe episodes are more likely to arise when transmission is uncontrolled and attack rates high.

Routine infection prevention and control measures

Standard infection control precautions (SICPs) should be used by all staff, in all care settings, at all times, for all patients whether infection is known to be present or not, to ensure the safety of those being cared for, staff and visitors in the care environment.

There are 10 elements of SICPs:

1. patient placement and assessment of infection risk
2. hand hygiene
3. respiratory and cough hygiene
4. personal protective equipment
5. safe management of the care environment
6. safe management of care equipment
7. safe management of healthcare linen
8. safe management of blood and body fluids
9. safe disposal of waste (including sharps)
10. occupational safety and managing prevention of exposure (including sharps)

When there is a suspected or confirmed outbreak additional measures may be required.

See also national guidance on infection prevention and control in adult social care settings and the ARI supplement to the IPC resource for adult social care.

Flu and COVID-19 immunisation for all staff should be encouraged, especially those in risk groups and for all residents.

Outbreak control measures

Outbreak control measures are additional to SICPs. Outbreak control measures are time-limited measures whose purpose is to interrupt further transmission and lessen the impact and duration of the outbreak. Outbreak control measures should be proportionate, risk assessed and time limited.

Examples of outbreak control measures may include:

• enhanced cleaning using 1,000 parts per million (ppm) chlorine-based solution or other product effective against respiratory viruses
• increase cleaning frequency of frequently touched surfaces in shared areas
• re-emphasis on hand and respiratory hygiene (including sectoral advice on the appropriate use of masks)
• reminders to regularly let fresh air in, in all areas
• restriction on movement of staff providing direct care to avoid ’seeding’ of outbreaks between different operational units and areas, floors and wings or between different care settings (for example for agency staff)
• cohorting of staff to care for symptomatic or positive and non-symptomatic or negative residents (as feasible and safe to do so within each operating unit, area or floor)
• proportionate reductions or postponement of non-essential communal activities
• proportionate reduction in admissions which may include temporary closure of home to further admissions and transfers (decision on closure does not fall to the HPT but to the care setting and the commissioning authority) – see Appendix 1
• transfers to other health and social care settings on a case-by-case risk assessment (important to communicate the situation to the receiving setting) – see Appendix 1
• for hospital outpatient appointments, advising the trust if potential infection control requirements and consider undertaking appointments remotely
• proportionate changes to visiting – this may include a reduction in the number of people entering and leaving a care home to reduce the spread of infection

Visiting should be facilitated unless there are exceptional circumstances, where facilitating a visit would pose a significant risk to the health or wellbeing of someone in the care home premises which cannot be mitigated through other precautions. End of life visits and visits from health professionals should always be facilitated, and CQC inspectors must be allowed entry to the care home. Please refer to ‘Supporting safer visiting in care homes during infectious illness outbreak’ for further visiting guidance.

Note: Any measures advised by HPTs or which the care homes choose to implement must be proportionate and risk based and should also consider residents’ wellbeing as well as the care home’s legal obligations.

The following individuals may either be involved in the response to an ARI outbreak in a care home or need to be informed about this. However, exact communication arrangements in these outbreaks will be generally defined according to local HPT protocols.

The individuals may include:

• health protection specialist from the local HPT
• care home manager
• care home IPC link practitioner (if identified)
• GPs
• local director of public health (DPH) or appropriate representatives from the local authority
• communications leads
• microbiologist from the local laboratory
• representative from IPC in the local trust (for awareness of potentially infectious patients from the home, requiring acute care)
• representative from community IPC teams (if applicable)
• NHS integrated care systems

Note: Although the HPT will provide public health advice in response to an outbreak, the care home management has the final responsibility for the safety of their staff and residents, including appropriate communication of information to staff, residents and visitors. The care home manager should be advised to escalate any operational issues in delivering services to the relevant commissioner or ICB, for example closure, staff shortages, PPE availability.

Residents

Symptomatic residents should be supported to stay away from others for a minimum of 5 days after the onset of respiratory symptoms. The movement of symptomatic residents should be minimised as far as possible prioritising the residents’ wellbeing as set out in the ‘Infection prevention and control (IPC) in adult social care: acute respiratory infection (ARI)’ guidance.

It is recognised that care homes are residential settings and that cohorting approaches (keeping cases together) is likely to be impractical in terms of moving people from their usual room of residence. This may particularly be the case where there are high numbers of people with dementia. For larger homes it is reasonable to attempt to restrict movement between areas (such as floors or units) so that cases in one area are not able to seed infection to another area, including through fomites such as surfaces and items in communal areas.

Within an area of the home that has cases, efforts should be made to prevent infection of other residents. In such areas there may be infected residents who are not yet symptomatic but may be or become an infection risk to un-infected residents.

The Covid-19 pandemic identified challenges in movement restrictions for patients living with dementia who ‘walk with purpose or intent’ . Such residents may find movement restrictions distressing and have difficulty complying. There is a limited evidence base to inform interventions (29). The British Geriatrics Society (BGS) advice is that sedation and physical constraint should not be used, with one-to-one care considered an option (if required this may need financial support to the home from commissioners), and meaningful activities provided for residents who walk with purpose. Community mental health teams may be able to advise on the use of such activities.

Protection of the immunosuppressed requires consideration. This could potentially be by shielding, sometimes described as reverse isolation or protective isolation. Immunosuppressed residents may also be more infectious, infectious for longer, and more prone to harbour drug resistant viruses. Therefore, it is also important to prevent transmission from these residents to others in the setting. Close adherence to IPC measures for and around immunosuppressed residents is recommended. See also on the influenza epidemiology section of this guidance regarding the potential for prolonged shedding.

If there is co-circulation of more than one respiratory virus, movement restrictions should take this into account.

Signage should be in place to help residents, staff and visitors recognise if there are any restricted movement areas within the care home. ‘Supporting safer visiting in care homes during infectious illness outbreaks’ can offer further guidance.

Infectious periods for residents are described below and summarised in Table 1.

For confirmed COVID-19 residents, they should be supported to avoid contact with others for a minimum of 5 days after the onset of symptoms. They can return to their normal activities after 5 days if they feel well and no longer have a high temperature. If the resident remains unwell, support to stay away from others should continue until they are well and acute symptoms have resolved, usually no longer than 10 days in total. Seek clinical advice for anyone who is still unwell or has a temperature, if not done already.

Post-acute symptoms such as a persistent dry ‘post-viral’ cough or fatigue do not require ongoing restrictions.

For confirmed or probable influenza, the patient should be supported to stay away from others until symptoms have resolved and for at least 3 days if treated with an influenza neuraminidase inhibitor and 5 days if not treated. There is evidence that older adults and people who are immunosuppressed may shed virus for longer and staff should be encouraged to consider this within an individual risk assessment of symptom resolution. Please see the influenza section for further information.

For seasonal respiratory viruses or ARI without a virological diagnosis, the resident should be supported to stay away from others from onset of symptoms until the resident no longer feels unwell and no longer has a high temperature. This is unlikely to be within 3 days of onset.

Table 1. Overview of infectious periods for residents with ARI according to respiratory guidance

Infection	Infectious period for residents
Confirmed Covid-19	Minimum 5 days from symptom onset. Continue supporting to stay away from others until feeling well and acute symptoms have resolved or to a maximum of 10 days.
Confirmed or probable influenza, not treated with an antiviral	The patient should be supported to stay away from others for at least 5 days or symptoms have resolved if longer.
Confirmed or probable influenza and has been treated with an antiviral	The patient should be supported to stay away from others for at least 3 days, or until symptoms have resolved if longer.
Other or unknown viruses	Support to stay away from others from onset of symptoms until the resident no longer feels unwell and no longer has a high temperature (unlikely to be less than 3 days).

During an ARI outbreak in a care home, residents who are close contacts should be supported to make proportionate changes to daily activities, considering the general public advice on risk reduction and minimising risk to people most vulnerable to severe illness.

Staff

In larger homes, separate staff should ordinarily be allocated to either areas (for example units or floors) where there are cases or to areas where there are no cases. This is to limit the risk of infection of residents by staff members. Staff should not ordinarily work at other care homes during an outbreak.

If possible, within an area that has both cases and non-cases, staff should work with only the symptomatic residents or the currently well residents to limit the risk of cross contamination of residents by staff members. Asymptomatic residents living in the areas with cases may have been exposed to a case and could themselves be infectious, or become infectious, so staff working with asymptomatic residents in an affected area of the home should not ordinarily also work with residents in unaffected areas of the home.

The care home may consider preferentially using staff vaccinated against influenza and COVID-19 (vaccinated at least 14 days beforehand) to care for symptomatic residents. Neither vaccine provides complete protection against infection and transmission, with this being particularly limited for COVID-19 vaccination.

Staff should always use PPE as described and adhere to control measures, regardless of vaccination status. Movement of staff between areas with and without symptomatic residents should also be restricted as far as possible.

Staff members who become unwell with ARI symptoms during an outbreak should leave work as soon as it is safe to do so.

Staff testing positive for COVID-19 should follow the ‘Infection prevention and control (IPC) in adult social care: acute respiratory infection (ARI)’ guidance. As a minimum they should follow advice for other ARI viruses as follows.

If staff members have symptoms of ILI or ARI and are not tested for Covid-19, they should remain off work until feeling well, with recovery from acute symptoms. This advice applies to suspected or confirmed influenza in staff; recovery from this is unlikely to be within 3 days of onset.

The acute symptoms are:

• high temperature, fever or chills
• sneezing
• runny or blocked nose
• muscle aches
• sore throat
• chesty cough
• hoarseness or wheezing

These may indicate active viral replication. Post-acute symptoms such as a persistent dry ‘post-viral’ cough or fatigue do not require staff to stay off work.

Depending on the causative organism, it can be appropriate for staff who would be at risk of complications if they become infected (for example pregnant or immunocompromised individuals) to avoid caring for symptomatic residents or confirmed cases in their infectious period. A risk assessment will need to be carried out on an individual basis.

Visitors

Families and regular visitors to residents of the care home should be advised by the home of the ARI outbreak, including display of signage at entrances.

Visiting should be facilitated unless there are exceptional circumstances and providers should put in place necessary and proportionate precautions to enable a visit to take place safely. If exceptional circumstances apply, visits from friends and family should be assessed on an individual basis as to whether they should occur. It may be appropriate to reduce or postpone visits if a visit would pose a significant risk to the health, safety, or wellbeing of someone on the care home premises, which cannot be mitigated through other measures.

Some forms of visiting should continue supported by individual risk assessments, these must take in to account the risk to the visitor. IPC measures should be taken to prevent transmission to the visitor, such as mask-wearing, hand hygiene and ventilation, if safe and appropriate.

Refer to specific guidance on visiting during outbreaks of ARIs.

In-room visits are usually more appropriate than meeting in communal areas with multiple residents present. Meeting spaces that can be readily decontaminated and ventilated, or meetings at windows, or outdoors if safe and in suitable weather can also be considered.

Closure of care home to new admissions and suspension of transfers

Once an outbreak of ARI is identified, closure of the home to new admissions may be considered. Decisions around potential new admissions during an outbreak are not straightforward and the care home should discuss this with the hospital discharge team, the commissioning authority, and the patient themselves or their relatives. Safe staffing levels may also be an important consideration.

See also Appendix 1 on discharges from hospitals to care homes during outbreaks.

Transfers to other social care providers (for example another care home) during the outbreak period should be avoided. For urgent transfers (for example where there is a safeguarding issue), decisions should be based on a risk assessment. The destination facility should be consulted, and advice provided on how to minimise infection risk.

Visits or transfers to acute medical facilities should be considered based on medical necessity. The destination facility should be informed in advance about the infection risk.

Pharmaceutical countermeasures

Specific pharmaceutical interventions against influenza and COVID-19 can protect the lives and health of residents during outbreaks.

Influenza antivirals

Detailed recommendations about the use of influenza antivirals can be found in guidance on use of antiviral agents for the treatment and prophylaxis of seasonal influenza.

In keeping with current recommendations by the National Institute for Health and Care Excellence (NICE) for treatment and prophylaxis, UKHSA recommends the prompt use of influenza antivirals for treatment of resident case-patients and prophylaxis of residents who may have been exposed or be at imminent risk of exposure to influenza.

The recommendation for use of antivirals in an outbreak situation may be made by a UKHSA HPT, following a local risk assessment, usually on the advice of the HPT consultant on duty. In periods where the CMO letter is in effect (enabling community prescribing of antivirals on the basis of influenza surveillance data), if a risk assessment has supported the use of antivirals this should not be delayed while waiting for influenza testing results. This can be reviewed once results are available as per the section on testing.

If a recommendation for post-exposure prophylaxis is made by the HPT for an outbreak, it is important that this is targeted as far as possible to those who are most likely to have been exposed to cases of influenza, or who would become exposed once likely latently infected residents become infectious. Within larger care homes, this may be possible by identifying specific units within the home where residents share specific common spaces. However, it is recognised that in some care homes, it may not be possible to identify such a subgroup due to small sizes or uncertain social mixing patterns. Due to the potential limited effectiveness of vaccination in the elderly, antivirals should be offered to such residents regardless of their influenza vaccination status.

Knowledge of the (likely) influenza strain (subtype) at the home and knowledge of expected vaccine protection against the strain (subtype) detected or suspected to be circulating at the home may also inform the risk assessment. However, vaccine protection is imperfect even when well-matched, and antiviral prophylaxis should be the default.

Post exposure prophylaxis is rarely required beyond the standard 10-day course for neuraminidase inhibitor antivirals.

While outside of the scope of outbreak response, in line with NICE guidance, antivirals can be initiated for prophylaxis of exposed residential contacts of single cases of influenza in care homes, equivalent to the use for at-risk household contacts of single cases in domestic settings. In the absence of demonstrable transmission in a setting, such use should usually be limited to the closest contacts only. Prophylaxis in these circumstances would be the responsibility of the registered GP of the resident exposed and would only be a possibility within the CMO declared flu season.

In relation to identification and risk assessment of exposed people, it is recognised that many symptomatic residents will be cared for in their own rooms, as explained in the residents section above. If a person with an ARI has been in a communal area while symptomatic, then a distance of 2 metres from that individual for 15 minutes or more can be used as a guide to identify exposed people for a risk assessment for antiviral prophylaxis.

Importantly, antivirals may only be prescribed by general practitioners on FP10s in England when the CMO has announced that influenza is circulating in the community. Further details of the restrictions are in section XVIIIB of the Drug Tariff. Local NHS commissioners should have arrangements in place for prescription of antiviral treatment and prophylaxis in outbreaks, for both when England is in the CMO ‘flu season’ and when it is not, as per NHS England guidance.

All details of first- and second-line treatments, including their indication, dosage and mode of administration can be found in the UKHSA guidelines on use of antiviral agents for the treatment and prophylaxis of seasonal influenza. In particular, prescribers should be referred to the oseltamivir dose requirements for individuals with known renal dysfunction, noting that while creatinine clearance drops with age, many older adults do not have chronic kidney disease (30). In emergency circumstances where renal function information will not be readily available, the British unity Geriatrics Special Interest Group have provided separate advice about antiviral prescribing in localised seasonal influenza outbreaks in care homes for older persons (see Appendix 3).

Treatment of influenza

Antivirals are recommended for treatment of resident case-patients and ideally should be provided within 48 hours (for adults) of onset of symptoms. Although antivirals provided up to 5 days after symptom onset can be beneficial and is encouraged if the resident is still unwell, the use of antivirals in such context is off-label and should be based on an individual clinical decision.

From a communicable disease control perspective, antiviral treatment of cases can markedly reduce their risk of infecting other people and therefore reduce the extent and duration of an outbreak (31).

Early identification of potential cases and urgent contact with relevant health services in the initial stages of the outbreak is therefore important to ensure that antivirals can be administered in a timely fashion. These recommendations are also applicable to symptomatic staff members who are in at-risk groups. Treatment of staff cases should be by their own GP in line with the NICE recommendations on influenza treatment.

For treatment, the choice between antiviral therapy (oseltamivir or zanamivir) will depend on several aspects, including the dominant circulating strain at the time, the patient’s characteristics, and whether or not the patient presents with complicated influenza.

PEP for influenza

As detailed in the NICE guidance TA158, antivirals can be considered for post exposure prophylaxis (PEP) among care home residents in at-risk groups during influenza outbreaks in care homes, regardless of their vaccination status.

Both oseltamivir and zanamivir can be used for influenza prophylaxis. However, this is dependent on the health status of the resident and the characteristics of the dominant circulating strains. Details about the choice of antiviral, their dosage and mode of administration can be found in the prophylaxis chapter of the UKHSA guidance on antivirals.

Antiviral prophylaxis is most effective if initiated within 48 hours of exposure. If there are concerns about high attack rates or high case fatality rates, prophylaxis could be considered more than 48 hours after last contact with a case or for longer durations following a risk assessment of the situation. However, it should be noted that such use is currently off-label.

In line with UKHSA antiviral guidance, antiviral prophylaxis can be considered:

• for staff who are in an at-risk group for influenza (including pregnancy) and who have not had the seasonal influenza vaccination (at least 14 days previously)
• if the vaccine is not well matched to circulating strains
• for those who would not be expected to have mounted an adequate response due to immunosuppression

This requires specific NHS commissioning as a non-residential exposure. Non-pharmaceutical measures such as surgical masks and SICPs are the main measures for reducing the risk of staff catching and spreading influenza during an outbreak.

Influenza antivirals if SARS-CoV-2 is also detected

Influenza antivirals have been safely used in SARS-CoV-2 co-infected patients and there is no known biological mechanism to suggest adverse impact. Co-infection with SARS-CoV-2 does not contraindicate the use of antivirals in a person infected with influenza. Data from early 2020 (prior to COVID-19 vaccines) indicates that co-infection was associated with higher mortality in hospitalised patients and so influenza antivirals may have particular clinical utility in such patients.

At time of writing there are no known interactions between neuraminidase inhibitors for influenza and the current recommended COVID-19 therapeutics.

COVID-19 treatments

In a COVID-19 outbreak, symptomatic eligible residents should be tested by LFD and those testing positive should be supported to access prompt treatment via their GP. NICE have made several drug recommendations for treatment, however, there are no currently recommended prophylactic medicines for COVID-19.

There is no expectation of HPT involvement with COVID-19 treatments. However, should an HPT become aware of a concern about accessibility of treatments to a specific population group, this should be escalated through the NHS channels responsible as a health equity concern.

Vaccination against influenza and COVID-19

Vaccination is a vital tool in the prevention of severe outcomes of influenza and COVID-19. Vaccination is important in reducing mortality and morbidity in residents and staff and also in reducing staff absences from work.

Seasonal influenza vaccination will be available to all care home staff and residents in the autumn and early winter. COVID-19 vaccination is organised in campaigns, typically with an autumn component. Staff and residents should be encouraged to accept both vaccinations when offered.

As 2 weeks are required for the immune response to vaccination to develop, influenza vaccination cannot be a substitute for PEP of exposed people in at-risk groups to prevent secondary cases. However, vaccination of unvaccinated people during an outbreak may provide an opportunity to protect against infection from other influenza strains at later points in the season.

Similarly, COVID-19 vaccines may not offer timely protection during an outbreak and other control measures are required. COVID-19 vaccination is therefore not a required intervention but vaccination during an outbreak for eligible but unvaccinated persons may reduce the likelihood and impact of a sustained outbreak and give protection against subsequent exposures.

Monitoring by the care home

Enhanced surveillance for further cases should be initiated by care home staff, to monitor all residents for elevated temperatures and other respiratory symptoms (as outlined above). It is important to identify infected residents as early as possible in order to implement outbreak control procedures, such as supporting residents to reduce their contact with others, to reduce the further spread of infection.

Care homes should be encouraged to contact the HPT or community IPC team (as per local protocols) again if:

• there is difficulty in applying the relevant outbreak control measures on which the home has been advised
• any of the residents or staff are hospitalised or die due to suspected or confirmed influenza, COVID-19 or other ARI virus — if this is for information only and advice is not required, they can inform the HPT by email without person-identifiable information
• there is a large increase in the number of cases
• there are concerns around public communication of the outbreak
• there is a suspected new outbreak

In the event of a staff death due to ARI, care homes should be advised of their requirements to risk assess and report under Reporting of Injuries, Diseases and Dangerous Occurrences Regulations (RIDDOR).

Recording and surveillance

Detailed information about ARI outbreaks should be recorded on HPZONE / CIMS or successor systems as per routine practice. Data will then be extracted by the national surveillance team. Care OBRA may also provide surveillance information if in use by the local systems and the HPT.

Outbreaks in care homes caused by influenza may predate widespread influenza activity in the community and therefore provide valuable information on:

• when influenza may be circulating
• the number of outbreaks
• effectiveness of vaccination and antivirals
• causative organisms
• dominant subtypes
• any changes that may occur to the virus (such as resistance acquisition)

Lifting of outbreak measures

Outbreak measures can be lifted 5 days after the onset of symptoms in the most recent symptomatic resident. A local risk assessment should underpin the decision to lift outbreak control measures.

This is long-established as best practice for proportionate care home outbreak control across ARI (1). This is also consistent with the epidemiological characteristics of influenza and later COVID-19 or SARS-CoV-2 variants. See also advice for cases on staying away from others and epidemiology section above, regarding the management of individuals at particular risk of prolonged shedding.

All residents should be monitored for up to a further 5 days after this to ensure they can access appropriate treatments where necessary. Further testing in an outbreak should only be done following an HPT risk assessment and on HPT advice in relation to specific concerns.

It is important to maintain SICP measures after the lifting of outbreak restrictions.

References

1. Read CA and others ‘Outbreaks of influenza A in nursing homes in Sheffield during the 1997-1998 season: implications for diagnosis and control’ Journal Public Health Medicine 2000: volume 22, issue 1, pages 116 to 120

2. Strausbaugh LJ and others ‘Infectious disease outbreaks in nursing homes: an unappreciated hazard for frail elderly persons’ Clinical Infection Disease 2003: volume 36, issue 7, pages 870 to 876

3. Stirrup O and others ‘Clinical Effectiveness of SARS-CoV-2 Booster Vaccine Against Omicron Infection in Residents and Staff of Long-term Care Facilities: A Prospective Cohort Study (VIVALDI)’ Open Forum Infectious Diseases 2022: volume 10, issue 1

4. Gallagher N and others ‘Characteristics of respiratory outbreaks in care homes during four influenza seasons 2011 to 2015’ Journal of Hospital Infection 2018: volume 99, issue 2, pages 175 to 180

5. Lessler J and others ‘Incubation periods of acute respiratory viral infections: a systematic review’ The Lancet Infectious Diseases 2009: volume 9, issue 5, pages 291 to 300

6. Patrozou E and LA Mermel ‘Does influenza transmission occur from asymptomatic infection or prior to symptom onset?’ Public Health Reports 2009: volume 124, issue 2, pages 193 to 196

7. Lee N and others ’Viral loads and duration of viral shedding in adult patients hospitalized with influenza’ The Journal of infection 2009: volume 200, issue 4, pages 492 to 500

8. Ryoo SM and others ‘Factors promoting the prolonged shedding of the pandemic (H1N1) 2009 influenza virus in patients treated with oseltamivir for 5 days’ Influenza Other Respiratory Viruses 2013: volume 7, issue 5, pages 833 to 837

9. Van den Hoogen BG and others ‘A newly discovered human pneumovirus isolated from young children with respiratory tract disease’ Nature Publishing Group 2001: volume 7, issue 6, pages 719 to 724

10. Falsey AR ‘Human metapneumovirus infection in adults’ The Pediatric Infectious Disease Journal 2008: volume 27, supplement 10, S80 to 83

11. Seynaeve D and others ‘Outbreak of Human Metapneumovirus in a Nursing Home: A Clinical Perspective’ Journal of the American Medical Directors Association 2020: volume 21, issue 1, pages 104 to 109 e101

12. Branche AR and Falsey AR ‘Parainfluenza Virus Infection’ Seminars in Respiratory and Critical Care Medicine 2016: volume 37, issue 4, pages 538 to 554

13. Fiore AE and others ‘Outbreak of pneumonia in a long-term care facility: antecedent human parainfluenza virus 1 infection may predispose to bacterial pneumonia’ Journal of the American Geriatrics Society 1998: volume 46, issue 9, pages 1112 to 1117

14. Lessler J and others ‘Incubation periods of acute respiratory viral infections: a systematic review’ The Lancet Infectious Diseases 2009: volume 9, issue 5, pages 291 to 300

15. Falsey AR and others ‘Viral respiratory infections in the institutionalized elderly: clinical and epidemiologic findings’ Journal of the American Geriatrics Society 1992: volume 40, issue 2, pages 115 to 119

16. Faulks JT and others ‘A Serious Outbreak of Parainfluenza Type 3 On a Nursing Unit’ Journal of the American Geriatrics Society 2000: volume 48, issue 10, pages 1216 to 1218

17. Doi, I, and others ‘An outbreak of acute respiratory infections due to human respiratory syncytial virus in a nursing home for the elderly in Ibaraki, Japan, 2014’ Japanese Journal of Infectious Diseases 2014: volume 67, issue 4, pages 326 to 328

18. Hart RJ ‘An outbreak of respiratory syncytial virus infection in an old people’s home’ The Journal of infection 1984: volume 8, issue 3, pages 259 to 261

19. Sorvillo FJ and others ‘An outbreak of respiratory syncytial virus pneumonia in a nursing home for the elderly’ Journal Infection 1984: volume 9, issue 3, pages 252 to 256

20. Osterweil D and D Norman ‘An outbreak of an influenza-like illness in a nursing home’ Journal of the American Geriatrics Society 1990: volume 38, issue 6, pages 659 to 662

21. Meijer A and others ‘Outbreak of respiratory syncytial virus infections in a nursing home and possible sources of introduction: the Netherlands, winter 2012/2013’ Journal of the American Geriatrics Society 2013: volume 61, issue 12, pages 2230 to 2231

22. Louie JK and others ‘Rhinovirus outbreak in a long-term care facility for elderly persons associated with unusually high mortality’ Clinical Infectious Disease 2005: volume 41, issue 2, pages 262 to 265

23. Zhu N and others ‘A Novel Coronavirus from Patients with Pneumonia in China, 2019’ New England Journal of Medicine 2020: volume 382, issue 8, pages 727 to 733

24. Goldman E ‘Exaggerated risk of transmission of COVID-19 by fomites’ The Lancet Infectious Diseases 2020: volume 20, issue 8, pages 892 to 893

25. Monto AS and others ‘Coronavirus Occurrence and Transmission Over 8 Years in the HIVE Cohort of Households in Michigan’ Journal Infectious Disease 2020: volume 222, issue 1, pages 9 to 16

26. Falsey AR and others ‘Should clinical case definitions of influenza in hospitalized older adults include fever’ Influenza Other Respiratory Viruses 2015: 9 Supply, supplement 1, pages 23 to 29

27. Huntley A, Cheston R, Corse D and Munafo J ‘Patients living with dementia who ‘walk with purpose or intent’ in the COVID-19 crisis’ (retrieved 7 June 2024)

29. Mallappallil M and others ‘Chronic kidney disease in the elderly: evaluation and management’ Clinical Practice (London) 2014: volume 11, issue 5, pages 525 to 535

30. Halloran ME and others (2006) ‘Antiviral Effects on Influenza Viral Transmission and Pathogenicity: Observations from Household-based Trials’ American Journal of Epidemiology 2006: volume 165, issue 2, pages 212 to 221

Appendix 1. Hospital discharge and admission to a care home during an outbreak

For further information, see Infection prevention and control in adult social care :acute respiratory infection and Supporting safer visiting in care homes during infectious illness outbreaks.

Discharge of hospitalised care home residents diagnosed with influenza or other non-SARS-CoV-2 respiratory viruses

Care home residents admitted to hospital with a diagnosis of influenza, or other respiratory viral infections may remain infectious to others even after discharge from hospital, and IPC measures as outlined in this guidance are indicated to prevent transmission to others.

Residents may be discharged from hospital at any point when the following criteria are satisfied.

1. In the view of the treating clinical staff, the resident has clinically recovered sufficiently to be discharged to a care home. Note that there is no requirement for the resolution of all symptoms or a minimum period of treatment.

2. All appropriate treatment will be completed after discharge.

3. Appropriate IPC measures to prevent transmission of infection, including single room dwelling or cohorting, will be continued outside hospital until a minimum of 5 days after the onset of symptoms. Note that in some circumstances (see above) it may be considered necessary to continue infection control measures beyond these periods.

4. The discharge is planned in accordance with local hospital policy.

Care homes may close wholly or in part to new admissions during outbreaks of influenza or other respiratory viruses. Where all the above criteria are satisfied, and appropriate outbreak control measures have been taken at the care home, residents hospitalised with a respiratory viral infection may return home during a period of closure occasioned by an outbreak of the same type of respiratory virus.

Discharge of care home residents hospitalised for reasons unrelated to influenza or respiratory viral infections to a care home during an outbreak of a respiratory virus

Care home residents hospitalised for reasons unrelated to influenza or respiratory viral infections should only be discharged back to a care home with an on-going respiratory virus outbreak after a careful assessment of the risk of exposure to cases of infection, as respiratory viral infections may have severe consequences in care home residents. Prevention is key to minimising impact.

The assessment of the likelihood of exposure to infection should take account of:

• the affected sections of the care home
• the location of the resident within the care home
• the overall geography of the care home
• contacts between residents or cross-over of staff or visitors between affected and - unaffected sections of the care home
• satisfactory compliance with IPC precautions by care home staff (including seasonal influenza vaccination uptake)

Appendix 2. Possible audit indicators for use by HPTs

Note: As local protocols vary between HPTs, not all indicators may be applicable. Audit indicators may need adapted as Care OBRA is rolled out.

Reporting and notification

1. Were there any delays in notification of outbreak to HPT? Assess time from onset date of outbreak to the date of notification/reporting to HPT.

Outbreak control guidance

2. Was appropriate outbreak control guidance given by HPT?

Swabbing

3. Was swabbing undertaken where indicated? If swabbing was not undertaken, was the rationale documented clearly on the appropriate case management system.

4. Were there any delays to swabbing/testing or receiving results?

Antiviral treatment and prophylaxis

5. If antivirals were indicated, and advised and prescribed to the resident’s within the correct timescales (proportion within 48 hours?)

6. Where antivirals were not advised, was rationale for this clearly documented on the appropriate case management system?

7. Was antiviral use advised prior to knowledge of swab results?

8. If antivirals were not prescribed – was the reason documented?

9. Were there any delays in residents or staff receiving antiviral treatment?

10. Were there any delays in residents or staff receiving antiviral prophylaxis?

11. Was there any difference in the initiation of antivirals for treatment vs prophylaxis? If yes, why?

Case management system recording

12. Was outbreak onset date noted?

13. Were metrics uploaded?

14. Was relevant context(s) added?

Appendix 3. British Geriatrics Society advice on antiviral prescribing

In November 2017, the British Geriatrics Society (BGS) issued advice about consideration of renal impairment in prescribing of antivirals in localised community outbreaks of seasonal influenza.

If an individual has a documented renal function within the last 6 months, which does not indicate renal impairment, the standard dose of oseltamivir antivirals can be prescribed. For individuals with a known renal impairment and where the prescriber has access to their renal function during an emergency outbreak, they can be prescribed an adjusted dose according to the UKHSA influenza guidelines or sources such as the British National Formulary (BNF) or summaries of product characteristics.

However, in an emergency outbreak response, where there is no information about the presence or absence of renal impairment (or lack of available routine renal function results from the past 6 months), there is a high likelihood of abnormal renal function in care home residents, so we would recommend a reduced daily dose of oseltamivir in all care home residents. This would be for a dose appropriate to creatinine clearance of 31 to 60 mL/min. We would not recommend routine measurement of renal function prior to treatment due to the logistical challenges of collecting bloods en masse in care home populations and the likely delays introduced by waiting for lab results to return in the community. Where time permits, checking renal function in specific patients at high risk of significant renal impairment, for example those on high dose diuretics, may be useful.

The importance of vaccination in both care home residents and staff is to be reinforced. Importantly, vaccination provides an opportunity for additional conversations, with families of care home patients who lack capacity to consent to therapy, to consider the relative merits of antiviral therapy in advance. It would be useful to discuss in advance, with residents’ families, the rationale for antiviral therapy in the event of outbreaks and to determine whether their relative would have been likely to want to opt out of such an approach. This would help to anticipate any issues relating to care home residents’ lack capacity to consent. Clinicians are advised to consider this in relation to their own local polices on capacity to consent.

Inhaled zanamivir should be primarily used for cognitively intact residents requiring antiviral therapy, such as those with recognised renal dysfunction or with suspected or confirmed oseltamivir-resistant influenza.

This advice was facilitated by Adam Gordon, of the University of Nottingham and BGS.