Official Statistics

National flu and COVID-19 surveillance report: 19 December (week 51)

Updated 19 December 2024

Applies to England

This report summarises the information from the surveillance systems which are used to monitor COVID-19 (caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)), influenza, and diseases caused by seasonal respiratory viruses in England. The report is based on data up to week 50 of 2024 (between 9 December and 15 December 2024).

Please note, due to the Christmas public holidays, a report will not be published in week 52. The next report will be published on Friday 3 January 2024.

Main points

The main messages of this report are:

• influenza activity increased across all indicators, and was at medium activity levels
• COVID-19 activity decreased across most indicators, and was at baseline levels
• respiratory syncytial virus (RSV) activity decreased across most indicators and was circulating at low levels of activity

Summary of all respiratory virus activity

Influenza activity

Influenza activity increased across all indicators and was at medium activity levels. Emergency department (ED) attendances for influenza-like illness (ILI) increased overall. The number of influenza-confirmed acute respiratory infections (ARI) incidents in week 50 increased compared with the previous week.

This season, so far influenza A(H1N1) has been the predominant subtype detected with recent increases in the number of A(H1N1) detections; there have also been a smaller number of A(H3N2) and a smaller number of influenza B detections.

Weekly influenza vaccine uptake for the 2024 to 2025 season is reported for week 50 (data up to 15 December 2024). Compared with the equivalent week last season (2023 to 2024), vaccine uptake is lower for those aged 2 years, slightly lower for those aged 3 years, and higher for pregnant women. Data is not comparable to previous seasons for those aged 65 years and over, and those aged under 65 years in clinical risk groups. This is because in previous seasons, these cohorts have been eligible from 1 September, rather than from 3 October this season.

Indicator	Trend	Level [note 1]	Comments
Laboratory surveillance	Increasing	Medium	Influenza positivity increased with a weekly mean positivity rate of 21.7% compared with 17.3% in the previous week
ILI general practice (GP) consultations	Increasing	Low	The weekly ILI consultation rate increased to 12.1 per 100,000 registered population in participating GP practices compared with 8.5 per 100,000 in the previous week
GP swabbing positivity	Increasing	Baseline	In week 48, among all tested samples, 7.3% were positive for influenza, compared with 5.3% in the previous week
Hospital admissions	Increasing	Medium	The overall weekly hospital admission rate for influenza increased to 8.72 per 100,000 compared with 5.79 per 100,000 in the previous week
Intensive care units (ICU)/High-dependency unit (HDU) admissions	Increasing	Medium	The overall ICU or HDU rate for influenza increased to 0.28 per 100,000 compared with 0.18 per 100,000 in the previous week

Note 1: these indicators use the moving epidemic method (MEM) to define thresholds to determine their respective levels of activity. Further information on this method can be found in Influenza surveillance in Europe: establishing epidemic thresholds by the Moving Epidemic Method. The MEM approach is well-established for influenza surveillance, however, for other indicators both the MEM and the mean standard deviation method (MSD) are experimental and may be subject to future revision. These approaches will be considered alongside expert opinion and triangulation of other data sources.

COVID-19 activity

COVID-19 activity decreased across most indicators and was circulating at baseline levels. ED attendances for COVID-19 remained stable. The number of reported SARS-CoV-2 confirmed ARI incidents in week 50 remained stable compared with the previous week.

In sequenced samples, the most prevalent lineage was KP.3.1.1.

By the end of week 50 2024 (week ending 15 December 2024) 58.6% of all people aged 65 years and over, and 23.2% of all people aged under 65 years and in a clinical risk group had been vaccinated with an autumn 2024 booster.

Indicator	Trend	Level [note 2]	Comments
Laboratory surveillance	Decreasing slightly	Baseline	COVID-19 PCR (polymerase chain reaction) positivity in hospital settings decreased slightly with a weekly mean positivity rate of 3.4% compared with 3.7% in the previous week
GP swabbing positivity	Decreasing	Baseline	In week 48, among all tested samples, 1.6% were positive for SARS-CoV-2, compared with 2.1% in the previous week
Hospital admissions	Decreasing	Baseline	The overall weekly hospital admission rate for COVID-19 decreased to 1.48 per 100,000 compared with 1.71 per 100,000 in the previous week
ICU/HDU admissions	Stable	Baseline	The overall ICU or HDU rate for COVID-19 remained stable at 0.06 per 100,000 compared with 0.06 per 100,000 in the previous week

Note 2: These indicators use the mean standard deviation method (MSD) to define thresholds to determine their respective levels of activity. Further information on this method can be found in Setting thresholds to determine COVID-19 activity levels using the mean standard deviation (MSD) method, England, 2022 to 2024. The MEM approach is well-established for influenza surveillance, however, for other indicators both the MEM and MSD are experimental and may be subject to future revision. These approaches will be considered alongside expert opinion and triangulation of other data sources.

Respiratory syncytial virus activity

RSV activity decreased across most indicators and was circulating at low levels overall. ED attendances for acute bronchiolitis decreased.

Indicator	Trend	Level [note 1]	Comments
Laboratory surveillance	Decreasing slightly	Low	RSV positivity decreased slightly to 11.8% compared with 12.6% in the previous week
GP swabbing positivity	Stable	Low	In week 48, among all tested samples, 15.8% were positive for RSV compared with 15.4% in the previous week
Hospital admissions	Decreasing	Low	The overall weekly hospital admission rate for RSV decreased to 2.81 per 100,000 compared with 3.22 per 100,000 in the previous week

Note 1: these indicators use the moving epidemic method (MEM) to define thresholds to determine their respective levels of activity. Further information on this method can be found in Influenza surveillance in Europe: establishing epidemic thresholds by the Moving Epidemic Method. The MEM approach is well-established for influenza surveillance, however, for other indicators both the MEM and MSD are experimental and may be subject to future revision. These approaches will be considered alongside expert opinion and triangulation of other data sources.

Other viruses

Indicator	Trend	Level [note 3]	Comments
Adenovirus	Stable	Low	Adenovirus positivity (laboratory surveillance) remained stable at 2.7%
Human metapneumovirus (hMPV)	Stable	Low	hMPV positivity (laboratory surveillance) remained stable at 2.7%
Parainfluenza	Increasing	Baseline	Parainfluenza positivity (laboratory surveillance) increased to 2.9%
Rhinovirus	Stable	Baseline	Rhinovirus positivity (laboratory surveillance) remained stable at 10.1%

Note 3: these indicators use the MEM (hMPV) and the MSD (adenovirus, parainfluenza and rhinovirus) to define thresholds to determine their respective levels of activity. Further information is available on the moving epidemic method (MEM) and the mean standard deviation method (MSD). The MEM approach is well-established for influenza surveillance, however, for other indicators both the MEM and MSD are experimental and may be subject to future revision. These approaches will be considered alongside expert opinion and triangulation of other data sources.

Laboratory surveillance

Laboratory-confirmed cases

The Second Generation Surveillance System (SGSS) captures test result information for notifiable infectious diseases, including COVID-19 and influenza, from laboratories in England. The unified sample dataset (USD), used to calculate the percentage tests positive for SARS-CoV-2 among all SARS-CoV-2 tests, stores all SARS-CoV-2 test results reported to SGSS, Respiratory DataMart, and UKHSA laboratories.

COVID-19 cases

As of 17 December 2024, there were a total of 933 COVID-19 cases identified in hospital settings in week 50, decreasing from 1,041 cases in the previous week. COVID-19 PCR positivity in hospital settings decreased slightly in week 50, with a weekly average positivity rate of 3.4% compared with 3.7% in the previous week. Positivity rates were highest in those aged 85 years and over at a weekly average positivity rate of 5.8%. This decreased when compared with week 49, when positivity rates were at 6.7% among those aged 85 years and over.

Figure 1. Weekly confirmed COVID-19 episodes tested in hospital settings, England

Figure 2. Daily percentage of tests positive for SARS-CoV-2 among all reported SARS-CoV-2 tests (7-day rolling average), England 2022 to present [note 4][note 5]

Note 4: data from previous seasons is aligned by day.

Note 5: testing policy and practice may change over time which can impact positivity rates, therefore comparisons over time should be interpreted with caution. Notable changes in testing policy occurred during 2022 to 2023, which are outlined in the data sources report.

Figure 3. Daily percentage of tests positive for SARS-CoV-2 among all reported SARS-CoV-2 tests by age group (7-day rolling average), England [note 6]

Note 6: the highlighted line corresponds to the age group in the subplot title, grey lines correspond to all other age groups.

Influenza cases

As of 17 December 2024, influenza positivity in week 50 increased with a weekly average positivity rate of 21.7% compared with 17.3% in the previous week. Influenza positivity rates were highest in those aged between 5 and 14 years at a weekly average positivity rate of 39.8%. This has increased from 30% among those aged between 5 and 14 years in week 49.

Figure 4. Daily percentage of tests positive for influenza among all reported influenza tests (7-day rolling average), England [note 4]

Note 4: data from previous seasons is aligned by day.

Figure 5. Daily percentage of tests positive for influenza among all reported influenza tests by age group (7-day rolling average), England [note 6]

Note 6: the highlighted line corresponds to the age group in the subplot title, grey lines correspond to all other age groups.

Respiratory DataMart System

Respiratory DataMart is a sentinel laboratory-based surveillance system where participating laboratories report positive and negative test results for a number of respiratory viruses from samples primarily taken in hospital. A small proportion of primary care samples are also included in this reporting.

In week 50, data is based on reporting from 8 out of the 14 sentinel laboratories.

In week 50, 8,039 respiratory specimens reported through the Respiratory DataMart System were tested for influenza. There were 1,422 positive samples for influenza: 848 influenza A (not subtyped), 35 influenza A (H3N2), 480 influenza A (H1N1)pdm09, and 61 influenza B. Overall, influenza positivity increased to 17.7% in week 50 compared with 14.7% in the previous week.

In week 50, 7,714 respiratory specimens reported through the Respiratory DataMart System were tested for SARS-CoV-2. There were 239 positive samples for SARS-CoV-2. SARS-CoV-2 positivity remained stable at 3.1% compared with 3.2% in the previous week, with the highest positivity in those aged under 5 years at 5.1%.

RSV positivity decreased slightly to 11.8%, with the highest positivity in those aged under 5 years at 30.5%.

Adenovirus positivity remained stable at 2.7%, with the highest positivity in those aged under 5 years at 6.3%.

Human metapneumovirus (hMPV) positivity remained stable at 2.7%, with the highest positivity in those aged under 5 years at 7.3%.

Parainfluenza positivity increased to 2.9%, with the highest positivity in those aged between 5 and 14 years at 7.2%.

Rhinovirus positivity remained stable at 10.1%, with the highest positivity in those aged under 5 years at 28.4%.

DataMart data is provisional and subject to retrospective updates.

Figure 6a. Respiratory DataMart weekly percentage of tests positive for influenza, SARS-CoV-2, RSV and rhinovirus, England [note 7]

Note 7: shading represents 95% confidence intervals.

Figure 6b. Respiratory DataMart weekly percentage of tests positive for adenovirus, hMPV and parainfluenza, England [note 7]

Note 7: shading represents 95% confidence intervals.

Figure 7. Respiratory DataMart weekly cases by influenza subtype, England

Figure 8. Respiratory DataMart weekly percentage testing positive for RSV by season, England

Figure 9. Respiratory DataMart weekly percentage testing positive for RSV by age, England [note 6]

Note 6: the highlighted line corresponds to the age group in the subplot title, grey lines correspond to all other age groups.

SARS-CoV-2 lineages

UKHSA conducts genomic surveillance of SARS-CoV-2 lineages.

This section provides an overview of circulating lineages in England, derived from data on sequenced PCR-positive SARS-CoV-2 samples in SGSS.

The prevalence of UKHSA-designated lineages among sequenced cases is presented in Figure 10.

To account for reporting delays, we report the proportion of lineages within COVID-19 cases that have had a sequenced positive sample between 11 November 2024 and 24 November 2024. Of those sequenced in this period 50.53% were classified as KP.3.1.1, 29.47% were classified as XEC, 12.63% were classified as JN.1, 1.05% were classified as KP.3 and 1.05% were classified as KP.3.1.

Please note that lineages will be grouped independently from their parent lineage once they reach sufficient prevalence. The data sources and methodology page contains more information on lineage groupings.

Figure 10. Prevalence of SARS-CoV-2 lineages amongst available sequenced cases for England from 11 December 2023 to 1 December 2024

Influenza virus characterisation

Between week 40 2024 (week ending 1 September 2024) and week 50 2024 (week ending 15 December 2024), the UKHSA Respiratory Virus Unit (RVU) has genetically characterised 325 influenza viruses, and identified 56 influenza A(H3N2) viruses, 232 influenza A(H1N1)pdm09 viruses and 37 influenza B viruses. Details of the characterised viruses are shown in Table 1. RVU has confirmed by genome sequencing the detection of live attenuated influenza vaccine (LAIV) viruses in 3 influenza A and 5 influenza B positive samples collected from children aged between 2 and 16 years.

Table 1. Number of influenza viruses characterised by genetic and antigenic analysis at the UKHSA respiratory virus unit since week 40 of 2024

Type	Subtype	Clade	Subclade	Reference virus name	Detections	Notes
A	H1N1	5a.2a	C.1.9	Not assigned yet	217
A	H1N1	5a.2a.1	D.3	Not assigned yet	8
A	H1N1	5a.2a.1	D	A/Victoria/4897/2022	4	A/Victoria/4897 is the (H1N1)pdm09 component of the 2024/2025 NH egg-based vaccine
A	H1N1	5a.2a.1	D.1	Not assigned yet	2
A	H1N1	5a.2a.1	D.5	Not assigned yet	1
A	H3N2	2a.3a.1	J.2	A/Sydney/878/2023	55
A	H3N2	2a.3a.1	G.1.3.1	Not assigned yet	1
B	Victoria	V1A.3a.2	C.5.1	B/Catalonia/2279261NS/2023	12
B	Victoria	V1A.3a.2	C.5.7	Not assigned yet	12
B	Victoria	V1A.3a.2	C.5.6	B/Brisbane/145/2023	11
B	Victoria	V1A.3a.2	C.3	B/Norway/5216/2023	2

Influenza virus antiviral susceptibility surveillance

Influenza positive samples are screened for mutations in the virus neuraminidase (NA) and the cap-dependent endonuclease of the polymerase acidic protein (PA) genes known to confer neuraminidase inhibitor (Oseltamivir and Zanamivir) or Baloxavir resistance, respectively. Results from this surveillance are given in Tables 2 and 3.

Table 2. Number of influenza viruses tested for inhibition by Oseltamivir and Zanamivir since week 40 of 2024 using whole genome sequencing

Subtype	Antiviral	Normal inhibition	Reduced inhibition	Highly reduced inhibition
H1N1pdm09	Oseltamivir	227	0	2
H1N1pdm09	Zanamivir	229	0	0
H3N2	Oseltamivir	56	0	0
H3N2	Zanamivir	56	0	0
B/Victoria	Oseltamivir	37	0	0
B/Victoria	Zanamivir	37	0	0

Patient 1: one sample with H275Y detected. Immune compromised adult patient known to have received oseltamivir treatment.

Patient 2: one sample with H275Y detected. Immune compromised adult patient known to have received oseltamivir treatment.

Table 3. Number of influenza viruses tested for inhibition by Baloxavir marboxil since week 40 of 2024 using whole genome sequencing

Subtype	Normal susceptibility	Reduced susceptibility
H1N1pdm09	180	0
H3N2	54	0
B/Victoria	36	0

Community surveillance

Acute respiratory infection incidents (ARI)

Data is presented on viral ARI incidents in different settings that are reported to UKHSA health protection teams (HPTs).

Please note that prior to July 2024, ARI incidents were recorded in HPZone, a previous case and incident management system. From July to September 2024, HPTs transitioned to a new system, the Case and Incident Management System (CIMS). Any interpretation of seasonal and temporal trends since 1 July 2024 should consider the likelihood of differences in reporting of ARI incidents due to this change.

There were 177 new ARI incidents reported in week 50 in England. These included:

• 144 incidents from care homes, of which 54 were due to influenza A, 16 were due to RSV, 10 were due to SARS-CoV-2, 9 were due to multiple pathogens, 7 were due to influenza (no type information available), 4 were due to other pathogens and 2 were due to parainfluenza

• 7 incidents from hospitals, of which 5 were due to influenza A and 1 was due to RSV

• 20 incidents from educational settings, of which 7 were due to influenza A, 2 were due to SARS-CoV-2, 1 was due to influenza B and 1 was due to multiple pathogens

• no incidents from prisons

• 6 incidents from other settings, of which 2 were due to influenza (no type information available), 1 was due to SARS-CoV-2 and 1 was due to influenza A

Figure 11. Number of ARI incidents by setting, England

Figure 12. Number of ARI incidents in all settings by virus type, England

FluSurvey (England)

FluSurvey is an internet-based participatory surveillance system based on the InfluenzaNet platform. It monitors trends of influenza-like illness (ILI) in the community using self-reported respiratory symptoms from registered participants.

The European Centre for Disease Control (ECDC) ILI case definition of sudden onset of symptoms with at least one of fever (chills), malaise, headache, muscle pain and at least one of cough, sore throat, shortness of breath is used for reporting. Please note that ILI is a broad definition and can include other respiratory illnesses such as COVID-19.

Healthcare use is presented as self-reported use of health services among participants meeting the ILI ECDC case definition. Where a person reports use of more than one health care service, secondary care will be indicated over primary care use and physical attendance to primary care will be indicated over use of remote services (for example, online NHS services, telephoning their GP or 111).

During week 50 2024:

• there were 1,113 participants who completed the weekly symptoms questionnaire

• 128 (11.5%) reported fever or cough and 46 (4.1%) met the ILI case definition

• 6.5% of participants meeting the ILI case definition reported contact with healthcare services as a result of self-reported symptoms; the most frequently reported contact was a visit to the GP

• the proportion of participants meeting the ILI case definition increased compared with the previous report week (4.1% compared with 3.6% in week 49)

Figure 13. Rates of fever or cough and influenza-like illness (ILI) per 1,000 FluSurvey participants, England

Figure 14. Proportion of healthcare use by type among FluSurvey participants meeting the influenza-like illness case definition, England

Flu Detector

Flu Detector is a web-based model which assesses internet-based search queries for influenza-like illness (ILI) in the general population. Daily ILI rate estimates are based on uniformly averaged search query frequencies for a weeklong period (including the current day and the 6 days before it). For week 50, the average daily ILI query rate increased compared with the previous week and was slightly above baseline activity (Figure 15).

Figure 15. Daily estimated ILI Google search query rates per 100,000 population, England

Syndromic surveillance

Syndromic surveillance collects data from various healthcare sources where presentations are classified by patterns of symptoms compatible with specific infections. In some settings, the syndromic diagnosis can be supplemented by (rapid) testing. In this report, ED attendances are displayed. Further details and data from other syndromic surveillance systems can be found in the syndromic surveillance weekly summaries.

During the week ending on 15 December 2024, ED attendances for acute respiratory infection increased and continued to be above seasonally expected levels. ED attendances for influenza-like illness increased and were in line with seasonally expected levels. ED attendances for COVID-19-like illness remained stable. ED attendances for acute bronchiolitis, a syndrome related to RSV infection, decreased slightly and were below seasonally expected levels.

Daily NHS 111 calls and online assessments for acute respiratory infection continued to increase but remained below seasonally expected levels. GP out-of-hours contacts for acute respiratory infections continued to increase. Contacts for influenza-like illness continued to increase.

Figure 16a. Daily emergency department attendances for acute respiratory infection nationally, England [note 8]

Note 8: seven-day moving average is adjusted for bank holidays. Grey columns show weekends and bank holidays.

Figure 16b. Daily emergency department attendances for acute respiratory infection by age group, England [note 9]

Note 9: scales vary in each graph to enable trend comparisons. The black line is the 7-day moving average adjusted for bank holidays.

Figure 17a. Daily emergency department attendances for COVID-19-like illness nationally, England [note 8]

Note 8: seven-day moving average is adjusted for bank holidays. Grey columns show weekends and bank holidays.

Figure 17b. Daily emergency department attendances for COVID-19-like illness by age group, England [note 9]

Note 9: scales vary in each graph to enable trend comparisons. The black line is the 7-day moving average adjusted for bank holidays.

Figure 18a. Daily emergency department attendances for ILI nationally, England [note 8]

Note 8: seven-day moving average is adjusted for bank holidays. Grey columns show weekends and bank holidays.

Figure 18b. Daily emergency department attendances for ILI by age group, England [note 9]

Note 9: scales vary in each graph to enable trend comparisons. The black line is the 7-day moving average adjusted for bank holidays.

Figure 19a. Daily emergency department attendances for acute bronchiolitis nationally, England [note 8]

Note 8: seven-day moving average is adjusted for bank holidays. Grey columns show weekends and bank holidays.

Figure 19b. Daily emergency department attendances for acute bronchiolitis by age group, England [note 9]

Note 9: scales vary in each graph to enable trend comparisons. The black line is the 7-day moving average adjusted for bank holidays.

Primary care surveillance

Primary care surveillance is undertaken in collaboration with the Royal College of General Practitioners (RCGP) Research and Surveillance Centre (RSC), using a national sentinel surveillance system of around 2,000 GP practices covering over 19 million registered patients of all ages across England. More information on the methodology can be found in the RCGP methodology report.

RCGP clinical indicators (England)

The weekly ILI consultation rate through the RCGP surveillance increased to 12.1 per 100,000 registered population in participating GP practices in week 50 compared with 8.5 per 100,000 in the previous week. This rate is in the low activity level (Figure 20). By age group, the highest rates were seen in those aged under 1 years (19.4 per 100,000), followed by those aged between 1 and 4 years (18.9 per 100,000).

The lower respiratory tract infections (LRTI) consultation remained stable at 136.4 per 100,000 in week 50 compared with 131.3 per 100,000 in the previous week.

Further details are available in the weekly RSC communicable and respiratory disease report for England.

Figure 20. RCGP ILI consultation rates per 100,000, all ages, England

MEM thresholds are based on data from the 2016 to 2017 season to the 2023 to 2024 season. Please note the 2019 to 2020, 2020 to 2021 and 2021 to 2022 seasons have been removed.

RCGP sentinel swabbing scheme in England

There were no results for week 49 and week 50.

809 samples were taken in week 48 through the GP sentinel swabbing, and 151 tested positive (Figure 21). As of week 4 2024, contemporaneous enterovirus differentiation has stopped. Starting from week 44 2024, reporting of rhinovirus and enterovirus has been grouped into rhinovirus/enterovirus. Starting from week 48 2024, samples with more than 10 days between the sample collection date and the symptom onset date have been excluded.

Among 545 tested samples in week 48, 1.6% were positive for SARS-CoV-2, 7.3% for influenza, 15.8% for RSV, 1.3% for adenovirus, 1.6% for hMPV, and 0% for enterovirus or rhinovirus (Figure 22). Due to the number of samples which have not yet been categorised, data should be interpreted with caution when compared with previous weeks. The proportion of detections among all tested samples is not calculated when the number of samples with a result is fewer than 50.

Figure 21. Number of samples tested for respiratory viruses in England by week, GP sentinel swabbing scheme [note 10] [note 11] [note 12]

Note 10: unknown category corresponds to samples with no result yet.

Note 11: starting from week 40 2024, testing for seasonal coronavirus has been suspended.

Note 12: reporting of rhinovirus and enterovirus follows a greater lag than for other respiratory pathogens.

Figure 22. Percentage of detected respiratory virus among all samples with completed testing in England by week, GP sentinel swabbing scheme [note 11] [note 12] [note 13]

Note 11: starting from week 40 2024, testing for seasonal coronavirus has been suspended.

Note 12: reporting of rhinovirus and enterovirus follows a greater lag than for other respiratory pathogens.

Note 13: data from the most recent week is not shown on this graph due to reporting delays.

Figure 23. Percentage of detected respiratory viruses among all samples with completed testing in England by age group, GP sentinel swabbing scheme, week 45 to week 48 [note 12] [note 13]

Note 12: reporting of rhinovirus and enterovirus follows a greater lag than for other respiratory pathogens.

Note 13: data from the most recent week is not shown on this graph due to reporting delays.

Figure 24. Weekly positivity for SARS-CoV-2, influenza and RSV in England, GP sentinel swabbing scheme [note 13]

Note 13: data from the most recent week is not shown on this graph due to reporting delays.

Secondary care

COVID-19 hospital and ICU or HDU admissions

Surveillance of COVID-19 hospitalisations to all levels of care and admissions to intensive care units (ICU) or high dependency units (HDU) are both mandatory, with data required from all acute NHS trusts in England.

Please note that SARI Watch data is provisional and subject to retrospective updates. ICU or HDU admission rates may also be affected by lags from admission to hospital to an ICU or HDU ward. Rates are presented per 100,000 trust catchment population.

COVID-19 hospitalisations for all levels of care in week 50 2024 based on 90 NHS trusts in England were as follows:

• the overall weekly hospital admission rate for COVID-19 decreased to 1.48 (compared with 1.71 per 100,000 in the previous week)

• hospital admission rates for COVID-19 were highest in the South West region (increasing to 2.25 per 100,000 compared with 1.76 in the previous week). Please refer to the slideset and supplementary data file for regional breakdowns

• the highest hospital admission rate for COVID-19 was in those aged 85 years and over (remained stable at 17.05 per 100,000 compared with 17.58 in the previous week)

COVID-19 ICU-HDU admissions in week 50 2024 based on 77 NHS trusts in England were as follows:

• the overall ICU or HDU rate for COVID-19 remained low at 0.06 per 100,000 (compared with 0.06 per 100,000 in the previous week). Note that with low rates in critical care, small random fluctuations may occur

• ICU or HDU admission rates for COVID-19 were highest in the Yorkshire and Humber region (remained low at 0.10 per 100,000 compared with 0.02 in the previous week). Please refer to the slideset and supplementary data file for regional breakdowns

• the highest ICU or HDU admission rate for COVID-19 was in those aged 85 years and over (increasing to 0.24 per 100,000 compared with 0.00 in the previous week)

Figure 25. Weekly overall COVID-19 hospital admission rates per 100,000 trust catchment population reported through SARI Watch mandatory surveillance, England [note 14]

Note 14: please note that a correction has been made to 2020 week numbers.

Figure 26. Weekly hospital admission rate by age group for new COVID-19 positive cases reported through SARI Watch mandatory surveillance, England [note 6]

Note 6: the highlighted line corresponds to the age group in the subplot title, grey lines correspond to all other age groups.

Figure 27. Weekly overall COVID-19 ICU or HDU admission rates per 100,000 trust catchment population reported through SARI Watch mandatory surveillance, England [note 14]

Note 14: please note that a correction has been made to 2020 week numbers.

Figure 28. Weekly ICU or HDU admission rate by age group for new COVID-19 positive cases reported through SARI Watch mandatory surveillance, England [note 6]

Note 6: the highlighted line corresponds to the age group in the subplot title, grey lines correspond to all other age groups.

Influenza hospital and ICU or HDU admissions

Surveillance of influenza hospitalisations to all levels of care is based on data from a small sentinel network of acute NHS trusts in England. Surveillance of admissions to ICU or HDU for influenza is mandatory with data required from all acute NHS trusts in England.

Please note that SARI Watch data is provisional and subject to retrospective updates. Rates are presented per 100,000 trust catchment population.

Influenza hospitalisations to all levels of care in week 50 2024 based on 25 sentinel NHS trusts in England were as follows:

• the overall weekly hospital admission rate for influenza increased to 8.72 per 100,000 (compared with 5.79 per 100,000 in the previous week)

• this rate is in the medium impact range (4.29 to less than 11.92 per 100,000)

• hospital admission rates for influenza were highest in those aged 85 years and over (32.63 per 100,000). Please refer to the slideset and supplementary data file for regional breakdowns

• there were 1023 new hospital admissions for influenza (904 influenza A(not subtyped), 62 influenza A(H1N1)pdm09, 2 influenza A(H3N2), and 55 influenza B)

Influenza ICU-HDU admissions in week 50 2024 based on 96 NHS trusts in England were as follows:

• the overall ICU or HDU rate for influenza increased to 0.28 per 100,000 (compared with 0.18 per 100,000 in the previous week). Note that with low rates in critical care, small random fluctuations may occur

• this rate is in the medium impact range (0.25 to 0.62 per 100,000)

• please refer to the slideset and supplementary data file for regional breakdowns

• there were 119 new ICU or HDU admissions for influenza (96 influenza A(not subtyped), 19 influenza A(H1N1)pdm09, 0 influenza A(H3N2), and 4 influenza B)

Figure 29. Weekly overall influenza hospital admission rates per 100,000 trust catchment population with MEM thresholds, reported through SARI Watch sentinel surveillance, England [note 15]

Note 15: please note that a correction has been made to 2019 week numbers.

Figure 30. Weekly influenza hospital admissions by influenza type, reported through SARI Watch sentinel surveillance, England

Figure 31. Weekly hospital admission rate by age group for new influenza reported through SARI Watch sentinel surveillance, England [note 6] [note 16]

Note 6: the highlighted line corresponds to the age group in the subplot title, grey lines correspond to all other age groups.

Note 16: please note this sentinel influenza surveillance did not routinely operate between weeks 21 and 39 2024 inclusive. The data presented in this period is based on a subset of trusts that voluntarily reported out of season.

Figure 32. Weekly overall influenza ICU or HDU admission rates per 100,000 trust catchment population with MEM thresholds, reported through SARI Watch mandatory surveillance, England [note 15]

Note 15: please note that a correction has been made to 2019 week numbers.

Figure 33. Weekly influenza ICU or HDU admissions by influenza type, reported through SARI Watch mandatory surveillance, England

Figure 34. Weekly ICU or HDU admission rate by age group for new influenza cases, reported through SARI Watch mandatory surveillance, England [note 6] [note 16]

Note 6: the highlighted line corresponds to the age group in the subplot title, grey lines correspond to all other age groups.

Note 16: please note this mandatory influenza surveillance did not routinely operate between weeks 21 and 39 2024 inclusive. The data presented in this period is based on a subset of trusts that voluntarily reported out of season.

RSV hospital admissions

Surveillance of respiratory syncytial virus (RSV) hospitalisations (excluding ICU or HDU admissions) is based on data from a small sentinel network of acute NHS trusts in England.

Please note that SARI Watch data is provisional and subject to retrospective updates. Rates are presented per 100,000 trust catchment population.

RSV hospitalisations, excluding ICU or HDU admissions, in week 50 2024 based on 22 sentinel NHS trusts in England were as follows:

• the overall weekly hospital admission rate for RSV decreased to 2.81 per 100,000 (compared with 3.22 per 100,000 in the previous week)

• in children aged under 5 years, the hospitalisation rate for RSV decreased to 23.18 per 100,000 (compared with 30.52 per 100,000 in the previous week)

• in adults aged 75 years and over, the hospitalisation rate for RSV decreased to 6.96 per 100,000 (compared with 8.17 per 100,000 in the previous week). Broken down further, rates were 5.53 per 100,000 in those aged between 75 and 84 years, and 10.55 per 100,000 in those aged 85 years and over in week 50

Figure 35. Weekly hospital admission rates (excluding ICU or HDU) of RSV positive cases per 100,000 population reported through SARI Watch sentinel surveillance, England [note 14] [note 17]

Note 14: please note that a correction has been made to 2020 week numbers.

Note 17: please note this sentinel RSV surveillance has routinely operated between week 40 and week 20 in previous seasons. RSV surveillance paused earlier following week 16 2024 to facilitate an earlier start in week 36 for the 2024 to 2025 season. In the 2020 to 2021 and 2021 to 2022 seasons only, surveillance was extended to week 39 due to urgent public health need.

Figure 36. Weekly hospital admission rates (excluding ICU or HDU) of RSV positive cases per 100,000 population in those aged under 5 years and aged over 75 years reported through SARI Watch sentinel surveillance, England [note 17]

Note 17: please note this sentinel RSV surveillance has routinely operated between week 40 and week 20 in previous seasons. RSV surveillance paused earlier following week 16 2024 to facilitate an earlier start in week 36 for the 2024 to 2025 season. In the 2020 to 2021 and 2021 to 2022 seasons only, surveillance was extended to week 39 due to urgent public health need.

Figure 37. Weekly count of hospital admissions of RSV positive cases reported through SARI Watch sentinel surveillance by level of care, England

Figure 38. Weekly hospital admission rates (excluding ICU or HDU) by age group for RSV cases reported through SARI Watch sentinel surveillance, England [note 6] [note 18]

Note 6: the highlighted line corresponds to the age group in the subplot title, grey lines correspond to all other age groups.

Note 18: please note this sentinel RSV surveillance did not routinely operate between weeks 17 and 35 2024 inclusive. The data presented in this period is based on a subset of trusts that voluntarily reported out of season.

ECMO admissions

Surveillance of extra corporeal membrane oxygenation (ECMO) admissions is based on data from severe respiratory failure (SRF) centres in the UK. Please refer to Sources of surveillance data for influenza, COVID-19 and other respiratory viruses for additional information.

Please note that SARI Watch data is provisional and subject to retrospective updates.

There were 5 new ECMO admissions reported in week 50 2024 in adults:

• 2 admissions were due to influenza (1 influenza A(H1N1)pdm09 and 1 influenza A H3N2)

• 3 were due to non-infectious causes

Please note that the other group includes other viral, bacterial or fungal ARI, suspected ARI, non-infection (such as asthma, primary cardiac and trauma) and sepsis of non-respiratory origin.

Figure 39. Laboratory confirmed ECMO admissions in adults (COVID-19, influenza and non-COVID-19 confirmed) to severe respiratory failure centres in the UK

Vaccine coverage

COVID-19 vaccine uptake in England

Cumulative data up to the end of week 50 2024 (Sunday 15 December 2024) was extracted from the Immunisation Information System (IIS), formerly the National Immunisation Management Service (NIMS). Data is extracted on the next working day following the end of the reporting week (Monday 16 December 2024). Age is calculated as age on date of extraction.

Data is provisional and subject to change following further validation checks. Any changes to historic figures will be reflected in the most recent publication.

Autumn 2024 campaign

The autumn 2024 data reported below covers any dose administered from 3 October 2024 provided there is at least 20 days from the previous dose. Eligible groups for the campaign are defined in Green Book chapter on COVID-19.

By the end of week 50 2024 (week ending 15 December 2024) 58.6% of all people aged 65 years and over, and 23.2% of all people aged under 65 years and in a clinical risk group, who are living and resident in England had been vaccinated with an autumn 2024 booster dose since 3 October 2024 (Figure 40).

Figure 40. Cumulative weekly COVID-19 vaccine uptake by target group in England [note 19]

Note 19: the month is taken from the Monday of an international organization for standardization (ISO) week.

For COVID-19 data on the real-world effectiveness of the COVID-19 vaccines, and on COVID-19 vaccination in pregnancy, please see the COVID-19 vaccine surveillance reports.

For COVID-19 management information on the number of COVID-19 vaccinations provided by the NHS in England, please see the COVID-19 vaccinations webpage.

For UK COVID-19 daily vaccination figures and definitions, please see the Vaccinations section of the UK COVID-19 dashboard.

On 19 December, monthly data for frontline healthcare workers has been published for the second time this autumn. This covers vaccinations that were given between 1 September and 30 November 2024 and is available under the joint flu and COVID-19 vaccine uptake report although vaccinations were only due to begin from 3 October 2024.

Influenza vaccination

Influenza vaccine uptake in GP patients

Due to the festive bank holidays weekly vaccine uptake will next be reported on Thursday 9 January 2025.

Weekly vaccine uptake data is provisional.

Influenza vaccination is reported by GP practice through the ImmForm website. ImmForm provides a secure online platform for vaccine uptake data collection for several immunisation surveys, including the seasonal influenza vaccine uptake collection. Details can be found at sources of surveillance data for influenza, COVID-19 and other respiratory viruses.

For the 2024 to 2025 season’s vaccination programme, children and pregnant women have been eligible since 1 September, while clinical risk groups, older adults (those aged over 65 years) and frontline healthcare workers have been eligible since 3 October. See the annual flu letter for more information. In previous seasons, these cohorts have all been eligible from 1 September.

Up to the end of week 50 of 2024 (Sunday 15 December 2024), the provisional proportion of people in England who had received an influenza vaccine this season in targeted groups was as follows:

Adults (98.6% of GP practices reporting through Immform):

• 37.6% in those aged under 65 years in a clinical risk group

• 33.1% in all pregnant women

• 73% in all those aged over 65 years

Children (98.7% of GP practices reporting):

• 40.3% in children aged 2 years

• 41.6% in children aged 3 years

Figure 41. Cumulative weekly influenza vaccine uptake by target group in England

This week, monthly data which cover vaccinations that were given between 1 September and 30 November 2024 for GP patients, school-aged children and frontline healthcare workers has been published for the second time this season. Data is not comparable to previous seasons for those aged 65 years and over, those aged under 65 years in clinical risk groups and frontline healthcare workers. This is because in previous seasons, these cohorts have been eligible from 1 September, rather than from 3 October this season.

The monthly GP report includes ethnicity data for at-risk groups, pregnant women, those aged 65 years and over, those aged 2 and 3 years, and primary and secondary school-aged children. For all cohorts, trends are similar to previous seasons.

Influenza vaccine uptake in school age children

This week, provisional monthly data on influenza vaccine uptake in children of school years Reception to Year 11 was published, showing the provisional proportion of children who received the 2024 to 2025 influenza vaccine via school, pharmacy or GP practice between 1 September and 30 November 2024. For primary school-aged children (aged 4 to 10 years), national vaccine uptake was 49.1% and for secondary school-aged children (aged 11 to 15 years) was 32.6%. This is the highest on record at this timepoint in the season.

Influenza vaccine uptake in frontline healthcare workers

This week, provisional monthly data on influenza vaccine uptake in frontline healthcare workers was published, showing vaccine uptake at national, commissioning region, and trust level, and by staff group, between 1 September and 30 November 2024. National vaccine uptake is 32.2%. Data is not comparable to previous seasons for frontline healthcare workers because in previous seasons, this cohort has been eligible from 1 September, rather than from 3 October this season.

Data sources and methodology

For additional information regarding data sources please refer to the sources of surveillance data for influenza, COVID-19 and other respiratory viruses.

Background information

Related statistics

COVID-19 deaths

For further information on COVID-19 related deaths in England please see the COVID-19 dashboard for death.

All-cause mortality assessment (England)

For further information on all-cause mortality in England please see the:

• Excess mortality within England post-pandemic method report, which uses Office for National Statistics (ONS) death registration data

• the all-cause mortality surveillance report, which uses the European mortality monitoring (EuroMOMO) model to identify weeks with higher than expected mortality

• the ONS all-cause excess mortality report

Syndromic surveillance

For further information on syndromic surveillance please see the syndromic surveillance weekly summaries.

Flu Detector

For further information on Flu detector please see the daily influenza-like illness rates.

Further information and contact details

Feedback and contact information

To provide feedback and for all queries relating to this document, please contact [email protected]

Official statistics

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Alternatively, you can contact OSR by emailing [email protected] or via the OSR website.

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