Non-typhoidal Salmonella data 2013 to 2022
Updated 18 April 2024
Applies to England
© Crown copyright 2024
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This publication is available at https://www.gov.uk/government/publications/salmonella-national-laboratory-and-outbreak-data/non-typhoidal-salmonella-data-2013-to-2022
Main points for 2022
The main points of the 2022 report are:
- the number of reported Salmonella cases in England returned to pre-COVID-19 pandemic levels, increasing from 5,033 cases in 2021 to 8,125 cases in 2022
- in 2022 Salmonella Enteritidis returned to being the most frequently reported serovar with laboratory reports increasing from 747 in 2021 to 2,044 in 2022 – reports of Salmonella Typhimurium also increased from 1,219 to 1,731, with Salmonella Typhimurium the second most commonly reported serovar in 2022
- the region that reported the highest number of Salmonella laboratory reports was London with 1,631 reports and was the region with the highest reporting rate with 18.4 reports per 100,000 population
- the age group with the highest number of laboratory reports was children below the age of 10
- August was the peak month for Salmonella reporting in 2022
Salmonella laboratory data 2013 to 2022
All data presented in this report is correct as of 7 February 2024. This report covers all non-typhoidal Salmonella serovars in England; data on typhoidal Salmonellae (S. Typhi and S. Paratyphi) is available in the Enteric fever annual reports.
Population- and deaths-data sourced from the Office for National Statistics (ONS). Mid-year population estimates for the relevant year for England were used to provide denominators for the calculation of rates. All rates are calculated as per 100,000 population.
COVID-19 pandemic
During 2020 and 2021 it is likely that the emergence of SARS-CoV-2 (COVID-19) and subsequent non-pharmaceutical interventions (NPIs) implemented to control COVID-19 transmission affected notifications of Salmonella infections to national surveillance in several ways.
These include, but are not limited to, changes which may have impacted ascertainment (for example changes in healthcare seeking behaviour, access to health care, availability or capacity of testing and so on) as well as changes which likely impacted incidence (for example limited foreign travel, closure of hospitality venues and attractions or behavioural changes around food consumption and so on) which will have also varied over time. Therefore, trends presented in this report should be interpreted with caution.
Additional in-depth analyses examining the impact of the COVID-19 pandemic are underway which will be published separately.
Annual data 2013 to 2022
All non-typhoidal Salmonella
Table 1. Annual laboratory reports of non-typhoidal Salmonella in England from 2013 to 2022
| Year | Number of laboratory reports | Laboratory reports per 100,000 population |
|---|---|---|
| 2013 | 7,104 | 13.19 |
| 2014 | 6,922 | 12.74 |
| 2015 | 8,188 | 14.95 |
| 2016 | 8,248 | 15.06 |
| 2017 | 8,670 | 15.59 |
| 2018 | 8,838 | 15.79 |
| 2019 | 8,398 | 14.92 |
| 2020 | 4,712 | 8.37 |
| 2021 | 5,033 | 8.90 |
| 2022 | 8,125 | 14.23 |
Figure 1 and Table 2 show the trend of non-typhoidal Salmonella laboratory reports in England from 2013 to 2022.
Figure 1. Annual laboratory reports of non-typhoidal Salmonella in England from 2013 to 2022
Salmonella Enteritidis
Table 2. Annual laboratory reports of Salmonella Enteritidis in England from 2013 to 2022
| Year | Number of laboratory reports | Laboratory reports per 100,000 population |
|---|---|---|
| 2013 | 1,983 | 3.68 |
| 2014 | 2,242 | 4.13 |
| 2015 | 2,362 | 4.31 |
| 2016 | 2,215 | 4.04 |
| 2017 | 2,324 | 4.18 |
| 2018 | 2,589 | 4.63 |
| 2019 | 2,514 | 4.47 |
| 2020 | 1,281 | 2.27 |
| 2021 | 747 | 1.32 |
| 2022 | 2,044 | 3.58 |
Figure 2 and Table 3 show the trend of Salmonella Enteritidis laboratory reports in England from 2013 to 2022.
Figure 2. Annual laboratory reports of Salmonella Enteritidis in England from 2013 to 2022
Salmonella Typhimurium
Table 3. Annual laboratory reports of Salmonella Typhimurium in England from 2013 to 2022
| Year | Number of laboratory reports | Laboratory reports per 100,000 population |
|---|---|---|
| 2013 | 1,472 | 2.73 |
| 2014 | 1,261 | 2.32 |
| 2015 | 1,621 | 2.96 |
| 2016 | 1,711 | 3.12 |
| 2017 | 1,965 | 3.53 |
| 2018 | 1,913 | 3.43 |
| 2019 | 1,568 | 2.79 |
| 2020 | 1,143 | 2.03 |
| 2021 | 1,219 | 2.16 |
| 2022 | 1,731 | 3.03 |
Figure 3 and Table 4 show the trend of Salmonella Typhimurium laboratory reports in England from 2013 to 2022.
Figure 3. Annual laboratory reports of Salmonella Typhimurium in England 2013 to 2022
Regional data
Table 4 displays the number of laboratory results per region in 2022. Regional classification is based on place of residence of reported cases and classified using NUTS1 codes.
Table 4. Regional distribution of laboratory reports of non-typhoidal Salmonella in England 2022
| Region | Laboratory reports | Laboratory reports per 100,000 population |
|---|---|---|
| East Midlands | 566 | 11.5 |
| East of England | 854 | 13.4 |
| London | 1631 | 18.4 |
| North East | 408 | 15.2 |
| North West | 920 | 12.2 |
| South East | 1,414 | 15.1 |
| South West | 830 | 14.4 |
| West Midlands | 765 | 12.7 |
| Yorkshire and the Humber | 737 | 13.3 |
Top 10 Salmonella serovars in 2022
Table 5 displays the number of laboratory reports for the top 10 most commonly reported Salmonella serovars in 2022.
Table 5. List of top 10 non-typhoidal Salmonella serovars reported in England 2022
| Serovar | Laboratory reports |
|---|---|
| Enteritidis | 2,044 |
| Typhimurium | 1,731 |
| Infantis | 310 |
| Newport | 226 |
| Mbandaka | 163 |
| Agona | 137 |
| Virchow | 136 |
| Java | 124 |
| Kentucky | 104 |
| Saintpaul | 97 |
Age and sex distribution in 2022
All non-typhoidal Salmonella
Figure 4 shows the age and sex distribution of non-typhoidal Salmonella laboratory reports in England during 2022. In this graph 76 laboratory reports were excluded where case age or sex was unknown. Overall, 50% of reported cases were male and the most affected age group was the 0-to-9 age category, accounting for 26% of total laboratory reports.
Figure 4. Age and sex distribution of laboratory reports of non-typhoidal Salmonella in England in 2022
Salmonella Enteritidis
Figure 5 shows the age and sex distribution of Salmonella Enteritidis laboratory reports in England during 2022. In this graph 5 laboratory reports were excluded where case age or sex was unknown. Overall, 50% of reported cases were male and the most affected age group was the 0-to-9 age category, accounting for 24% of total laboratory reports.
Figure 5. Age and sex distribution of laboratory reports of Salmonella Enteritidis in England in 2022
Salmonella Typhimurium
Figure 6 shows the age and sex distribution of Salmonella Typhimurium laboratory reports in England during 2022. In this graph 3 laboratory reports were excluded where case age or sex was unknown. Overall, 50% of reported cases were male and the most affected age group was the 0-to-9 age category, accounting for 36% of total laboratory reports.
Figure 6. Age and sex distribution of laboratory reports of Salmonella Typhimurium in England in 2022
Index of Multiple Deprivation in 2022
Table 6 displays the number of Salmonella cases of Index of Multiple Deprivation (IMD) decile. The deprivation level of an area (IMD decile) was mapped to each case using patient home postcode. Valid postcodes were unavailable for 207 cases so could not be matched to IMD decile.
Table 6. Number of Salmonella cases per IMD decile in England 2022
| IMD deciles | Total number of cases (%) |
|---|---|
| 1 (Most deprived) | 751 (9) |
| 2 | 780 (10) |
| 3 | 831 (10) |
| 4 | 833 (10) |
| 5 | 821 (10) |
| 6 | 815 (10) |
| 7 | 795 (10) |
| 8 | 782 (10) |
| 9 | 784 (10) |
| 10 (Least deprived) | 726 (9) |
| Unknown | 207 (3) |
| Total | 8,125 (100) |
Seasonal variation in 2022
Figure 7 shows the seasonal trend of laboratory reporting for all non-typhoidal Salmonella, Salmonella Enteritidis and Salmonella Typhimurium in England during 2022 by month. In 2022, the number of laboratory reports per month of all non-typhoidal Salmonella broadly followed the same trend as the median of the previous 5 years, excluding 2020 and 2021 (2015 to 2019), however peak reporting for 2022 occurred in August rather than September.
Figure 7. Seasonality of laboratory reports of all non-typhoidal Salmonella, Salmonella Enteritidis and Salmonella Typhimurium in England in 2022
Foodborne outbreak data in 2022
Table 7. Foodborne outbreaks of non-typhoidal Salmonella reported in England (Note 1) in 2022
| Agent | Total affected | Laboratory confirmed | Hospitalised (Note 2) | Deaths (Note 2) | Setting | Food description |
|---|---|---|---|---|---|---|
| Salmonella Java | 33 | 16 | 4 | Food service: restaurant | Fresh coriander leaves | |
| Salmonella Salamae | 22 | 22 | Unknown | 0 | National | Unknown |
| Salmonella Gueuletapee | 47 | 47 | 8 | 0 | National | Kebab meat |
| Salmonella Infantis | 50 | 50 | 3 | 0 | National | Chicken |
| Salmonella Agona | 16 | 16 | 2 | 0 | National | Cucumbers |
| Salmonella Mbandaka | 112 | 112 | 10 | 1 | National | Chicken |
| Salmonella Infantis | 58 | 58 | 15 | 0 | National | Chicken |
| Salmonella Typhimurium | 5 | 5 | 0 | Farm | Raw drinking milk | |
| Salmonella Typhimurium | 133 | 133 | 26 | 0 | National | Chocolate products |
| Salmonella Typhimurium | 24 | 24 | 8 | 2 | National | Ready meal |
| Salmonella Typhimurium | 91 | 91 | 7 | 0 | National | Meat products |
Note 1: Number of cases affected and number laboratory confirmed is for cases resident in England. Where the outbreak spanned more than one year, only the number of cases reported in 2022 is included in the table.
Note 2: Clinical outcome is not known for all cases and the data reported represents cases who have hospitalisations or deaths reported to national surveillance.
Conclusions
Overall in 2022 the number of Salmonella laboratory reports were similar to that seen in previous years (excluding 2020 and 2021 – data from these years should be interpreted with caution given the impact of the COVID-19 pandemic on national surveillance).
Similar to 2019, the highest number of laboratory-confirmed cases were in London. In 2022, August was the peak month for reported cases of Salmonella, whereas the peak reporting month based upon the 5-year median from 2015 to 2019 was September. Representation of male to female cases was approximately 50% (where case gender was known), with 0-to-9 being the most affected age group. Salmonella Enteritidis was the most commonly reported serovar, consistent with previous years prior to the COVID-19 pandemic.
Eleven outbreaks of Salmonella were reported to national surveillance in 2022, comprising 591 cases (574 of whom were laboratory-confirmed).
These outbreaks were associated with the consumption of multiple different food vehicles, including:
- fresh coriander leaves
- kebab meat
- chicken
- cucumbers
- raw drinking milk
- chocolate products
- meat products
Data sources
This report was produced using data derived from 2 data sources. The first is the UK Health Security Agency (UKHSA), formerly Public Health England (PHE), Second Generation Surveillance System (SGSS). This is a live laboratory reporting system therefore numbers are subject to change. In 2014, PHE upgraded the laboratory reporting system so direct comparisons between data reported from the previous system (LabBase2) and the new system (SGSS) requires cautious interpretation.
The second data source is the Gastrointestinal Infections and Food Safety (One Health) (GIFSOH) division’s eFOSS (electronic foodborne and non-foodborne outbreak surveillance system), which is also a live surveillance system and therefore numbers are subject to change.
Data caveats
This report was produced using laboratory data for England only, therefore the number of Salmonella laboratory reports published in previous reports which include data from other UK countries will be higher than those included in this report.
Acknowledgements
We are grateful to:
- the microbiologists and local authorities, health protection and environmental health specialists who have contributed data and reports to national surveillance systems
- the epidemiologists and information officers who have worked on the national surveillance of intestinal infectious diseases
- colleagues in the Gastrointestinal Bacterial Reference Unit (GBRU) for providing the Reference Laboratory Services and laboratory surveillance functions and expertise
- UKHSA (formerly PHE) Information Management Department for maintenance and quality assurance of UKHSA national surveillance databases used for gastrointestinal infections (GI) pathogen surveillance at the national level
- UKHSA (formerly PHE) Local Public Health Laboratories and Food Water and Environmental Microbiology Services for providing a surveillance function for GI pathogens and testing of food and environmental samples routinely and during outbreak investigations
- all colleagues who have investigated and reported outbreaks to the eFOSS surveillance database
Prepared by: Gastrointestinal Infections and Food Safety (One Health) Division, UKHSA.
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