Official Statistics

National flu and COVID-19 surveillance report: 21 November (week 47)

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 46 of 2024 (between 11 November and 17 November 2024).

Main points

The main messages of this report are:

• influenza activity increased across some indicators but remained within baseline activity levels
• COVID-19 activity decreased across most indicators, and was at baseline levels
• respiratory syncytial virus (RSV) activity increased and was circulating at medium levels of activity, with increases seen in most age groups

Summary of respiratory virus activity

Influenza activity

Influenza activity increased across some indicators and was circulating at baseline levels. Emergency department (ED) attendances for influenza-like-illness (ILI) increased overall. The number of influenza-confirmed ARI incidents in week 46 increased compared with the previous week.

Weekly influenza vaccine uptake for the 2024 to 2025 season is reported for week 46 (data up to 17 November 2024). Compared with the equivalent week last season (2023 to 2024), vaccine uptake is slightly lower for those aged 2 years, comparable 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	Baseline	Influenza positivity increased with a weekly mean positivity rate of 3.9% compared with 3.3% in the previous week
ILI general practice (GP) consultations	Stable	Baseline	The weekly ILI consultation rate remained stable at 3.7 per 100,000 registered population in participating GP practices compared with 3.8 per 100,000 in the previous week
GP swabbing positivity	Decreasing slightly	Baseline	In week 45, among all tested samples, 1.5% were positive for influenza, compared with 1.6% in the previous week
Hospital admissions	Increasing	Baseline	The overall weekly hospital admission rate for influenza increased to 1.28 per 100,000 compared with 1.05 per 100,000 in the previous week
Intensive care units (ICU)/High-dependency unit (HDU) admissions	Stable	Baseline	The overall ICU or HDU rate for influenza remained stable at 0.02 per 100,000 compared with 0.04 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 approach 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 acute respiratory infections (ARI) incidents in week 46 increased compared with the previous week.

By the end of week 46 2024 (week ending 17 November 2024) 54.2% of all people aged 65 years and over, and 20.9% 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	Baseline	In week 44, COVID-19 PCR (polymerase chain reaction) positivity in hospital settings decreased with a weekly mean positivity rate of 9.3% compared with 11.9% in the previous week
GP swabbing positivity	Decreasing	Baseline	In week 45, among all tested samples, 2.2% were positive for SARS-CoV-2, compared with 5.4% in the previous week
Hospital admissions	Decreasing	Baseline	The overall weekly hospital admission rate for COVID-19 decreased to 1.82 per 100,000 compared with 2.19 per 100,000 in the previous week
ICU/HDU admissions	Stable	Baseline	The overall ICU or HDU rate for COVID-19 remained stable at 0.07 per 100,000 compared with 0.07 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 approach 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 increased further and was circulating at medium levels overall, with increases now seen in most age groups. ED attendances for acute bronchiolitis increased.

Indicator	Trend	Level [note 1]	Comments
Laboratory surveillance	Increasing	Low	RSV positivity increased to 12.1% compared with 9.3% in the previous week
GP swabbing positivity	Decreasing	Baseline	In week 45, among all tested samples, 4% were positive for RSV compared with 7.6% in the previous week
Hospital admissions	Increasing	Medium	The overall weekly hospital admission rate for RSV increased to 3.14 per 100,000 compared with 2.07 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 approach 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	Increasing	Low	Adenovirus positivity (laboratory surveillance) increased to 2.9%
Human metapneumovirus (hMPV)	Stable	Baseline	hMPV positivity (laboratory surveillance) remained stable at 2%
Parainfluenza	Stable	Baseline	Parainfluenza positivity (laboratory surveillance) remained stable at 3%
Rhinovirus	Increasing slightly	Low	Rhinovirus positivity (laboratory surveillance) increased slightly to 13.7%

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 approach 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

A technical issue has prevented UKHSA from processing the data used to provide the percentage of tests positive for SARS-CoV-2 among all reported SARS-CoV-2 tests (Figures 2 and 3). Work is underway to resolve the issue and resume reporting as soon as possible. The data presented in figures 2 and 3 was last updated on 7 November 2024.

As of 19 November 2024, there were a total of 1,699 COVID-19 cases identified in hospital settings in week 44, decreasing from 2,393 cases in the previous week. COVID-19 PCR positivity in hospital settings decreased in week 44, with a weekly average positivity rate of 9.3% compared with 11.9% in the previous week. Positivity rates were highest in those aged 85 years and over at a weekly average positivity rate of 16.4%. This decreased when compared with week 43, when positivity rates were at 20.1% among those aged 85 years and over.

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

Figure 2. Percentage of tests positive for SARS-CoV-2 among all reported SARS-CoV-2 tests, England 2022-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 2022-23, which are outlined in the data sources document.

Figure 3. Percentage of tests positive for SARS-CoV-2 among all reported SARS-CoV-2 tests by age group, 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 19 November 2024, influenza positivity in week 46 increased with a weekly average positivity rate of 3.9% compared with 3.3% in the previous week. Influenza positivity rates were highest in those aged between 5 and 14 years at a weekly average positivity rate of 11.6%. This has increased from 8.8% among those aged between 5 and 14 years in week 45.

Figure 4. Percentage of tests positive for influenza among all reported influenza tests, England [note 4]

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

Figure 5. Percentage of tests positive for influenza among all reported influenza tests by age group, 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 46, data is based on reporting from 9 out of the 14 sentinel laboratories.

In week 46, 5,878 respiratory specimens reported through the Respiratory DataMart System were tested for influenza. There were 256 positive samples for influenza: 127 influenza A (not subtyped), 30 influenza A (H3N2), 91 influenza A (H1N1)pdm09, and 11 influenza B. Overall, influenza positivity increased to 4.4% in week 46 compared with 3.5% in the previous week.

In week 46, 5,682 respiratory specimens reported through the Respiratory DataMart System were tested for SARS-CoV-2. There were 220 positive samples for SARS-CoV-2. SARS-CoV-2 positivity decreased to 3.9% compared with 5.6% in the previous week, with the highest positivity in those aged 80 years and over at 6.5%.

RSV positivity increased to 12.1%, with the highest positivity in those aged under 5 years at 39.5%.

Adenovirus positivity increased to 2.9%, with the highest positivity in those aged under 5 years at 5.7%.

Human metapneumovirus (hMPV) positivity remained stable at 2%, with the highest positivity in those aged under 5 years at 3.8%.

Parainfluenza positivity remained stable at 3%, with the highest positivity in those aged under 5 years at 8.2%.

Rhinovirus positivity increased slightly to 13.7%, with the highest positivity in those aged under 5 years at 29.6%.

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 14 October 2024 and 27 October 2024. Of those sequenced in this period 42.91% were classified as XEC, 38.75% were classified as KP.3.1.1, 9.69% were classified as JN.1, 1.73% were classified as KP.3, 1.38% were classified as KP.3.1 and 1.04% were classified as KP.2.

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

Figure 10. Prevalence of SARS-CoV-2 lineages amongst available sequenced cases for England from 13 November 2023 to 3 November 2024

Influenza virus characterisation

Between week 40 2024 (week ending 1 September 2024) and week 46 2024 (week ending 17 November 2024), the UKHSA Respiratory Virus Unit (RVU) has genetically characterised 177 influenza viruses, and identified 38 influenza A(H3N2) viruses, 123 influenza A(H1N1)pdm09 viruses and 16 influenza B viruses. Details of the characterised viruses is shown in Table 1. RVU has confirmed by genome sequencing the detection of live attenuated influenza vaccine (LAIV) viruses in one influenza A and three 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	116
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.3	Not assigned yet	2
A	H1N1	5a.2a.1	D.1	Not assigned yet	1
A	H3N2	2a.3a.1	J.2	A/Sydney/878/2023	37
A	H3N2	2a.3a.1	G.1.3.1	Not assigned yet	1
B	Victoria	V1A.3a.2	C.5.6	B/Brisbane/145/2023	7
B	Victoria	V1A.3a.2	C.5.1	B/Catalonia/2279261NS/2023	4
B	Victoria	V1A.3a.2	C.5.7	Not assigned yet	4
B	Victoria	V1A.3a.2	C.3	B/Norway/5216/2023	1

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	122	0	0
H1N1pdm09	Zanamivir	122	0	0
H3N2	Oseltamivir	38	0	0
H3N2	Zanamivir	38	0	0
B/Victoria	Oseltamivir	16	0	0
B/Victoria	Zanamivir	16	0	0

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	94	0
H3N2	38	0
B/Victoria	16	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 55 new ARI incidents reported in week 46 in England. These included:

• 44 incidents from care homes, of which 13 were due to SARS-CoV-2, 5 were due to influenza A, 5 were due to multiple pathogens and 4 were due to other pathogens

• 3 incidents from hospitals, of which 2 were due to influenza A and 1 was due to SARS-CoV-2

• 7 incidents from educational settings, of which 3 were due to RSV and 2 were due to influenza A

• no incidents from prisons

• 1 incident from other settings, of which 1 was due to SARS-CoV-2

Figure 11. Number of ARI incidents by setting, England

Figure 12. Number of ARI incidents in all settings by virus type, 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 46, the average daily ILI query rate increased compared with the previous week and was below baseline activity (Figure 13).

Figure 13. 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 17 November 2024, ED attendances for acute respiratory infection increased and were in line with seasonally expected levels. ED attendances for influenza-like illness increased slightly 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, remained stable and were below seasonally expected levels.

Daily NHS 111 calls for acute respiratory infection increased. GP out-of-hours contacts for acute respiratory infections increased and were in line with expected seasonal activity. Contacts for influenza-like illness decreased.

Figure 14a. 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 14b. 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 15a. 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 15b. 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 16a. 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 16b. 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 17a. 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 17b. 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 remained stable at 3.7 per 100,000 registered population in participating GP practices in week 46 compared with 3.8 per 100,000 in the previous week. This rate is in the baseline activity level (Figure 18). By age group, the highest rates were seen in those aged between 1 and 4 years (4.7 per 100,000), followed by those aged between 15 and 44 years (4.2 per 100,000).

The lower respiratory tract infections (LRTI) consultation remained stable at 109.1 per 100,000 in week 46 compared with 104.6 per 100,000 in the previous week.

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

Figure 18. 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 46.

658 samples were taken in week 45 through the GP sentinel swabbing, and 26 tested positive (Figure 19). 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.

Among all tested samples, 2.2% were positive for SARS-CoV-2, 1.4% for influenza, 4% for RSV, 1.4% for adenovirus, 0.4% for hMPV, and 0% for enterovirus or rhinovirus (Figure 20). 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 19. 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 20. 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 21. Percentage of detected respiratory viruses among all samples with completed testing in England by age group, GP sentinel swabbing scheme, week 42 to week 45 [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 22. 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 46 2024 based on 91 NHS trusts in England were as follows:

• the overall weekly hospital admission rate for COVID-19 decreased to 1.82 (compared with 2.19 per 100,000 in the previous week)

• hospital admission rates for COVID-19 were highest in the North East region (decreasing to 3.42 per 100,000 compared with 3.94 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 (decreasing to 19.25 per 100,000 compared with 21.99 in the previous week)

COVID-19 ICU-HDU admissions in week 46 2024 based on 80 NHS trusts in England were as follows:

• the overall ICU or HDU rate for COVID-19 remained low at 0.07 per 100,000 (compared with 0.07 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 East of England region (remained stable at 0.14 per 100,000 compared with 0.14 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 between 75 and 84 years (increasing to 0.29 per 100,000 compared with 0.24 in the previous week)

Figure 23. 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 24. 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 25. 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 26. 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 46 2024 based on 25 sentinel NHS trusts in England were as follows:

• the overall weekly hospital admission rate for influenza increased to 1.28 per 100,000 (compared with 1.05 per 100,000 in the previous week)

• this rate is in the baseline impact range (less than 1.77 per 100,000)

• hospital admission rates for influenza were highest in those aged between 0 to 4 years (3.67 per 100,000). Please refer to the slideset and supplementary data file for regional breakdowns

• there were 141 new hospital admissions for influenza (99 influenza A(not subtyped), 27 influenza A(H1N1)pdm09, 4 influenza A(H3N2), and 11 influenza B)

Influenza ICU-HDU admissions in week 46 2024 based on 98 NHS trusts in England were as follows:

• the overall ICU or HDU rate for influenza remained low at 0.02 per 100,000 (compared with 0.04 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 baseline impact range (less than 0.1 per 100,000)

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

• there were 10 new ICU or HDU admissions for influenza (5 influenza A(not subtyped), 2 influenza A(H1N1)pdm09, 1 influenza A(H3N2), and 2 influenza B)

Figure 27. 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 28. Weekly influenza hospital admissions by influenza type, reported through SARI Watch sentinel surveillance, England

Figure 29. 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 30. 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 31. Weekly influenza ICU or HDU admissions by influenza type, reported through SARI Watch mandatory surveillance, England

Figure 32. 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 46 2024 based on 21 sentinel NHS trusts in England were as follows:

• the overall weekly hospital admission rate for RSV increased to 3.14 per 100,000 (compared with 2.07 per 100,000 in the previous week)

• in children aged under 5 years, the hospitalisation rate for RSV increased to 39.19 per 100,000 (compared with 24.32 per 100,000 in the previous week)

• in adults aged 75 years and over, the hospitalisation rate for RSV increased to 3.68 per 100,000 (compared with 2.99 per 100,000 in the previous week). Broken down further, rates were 2.20 per 100,000 in those aged between 75 and 84 years, and 7.47 per 100,000 in those aged 85 years and over in week 46

Figure 33. 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 34. 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 35. Weekly count of hospital admissions of RSV positive cases reported through SARI Watch sentinel surveillance by level of care, England

Figure 36. 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 2 new ECMO admissions reported in week 46 2024 in adults:

• all admissions were due to an ARI (other viral, bacterial or fungal)

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 37. 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 46 2024 (Sunday 17 November 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 18 November 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 46 2024 (week ending 17 November 2024) 54.2% of all people aged 65 years and over, and 20.9% 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 38).

Figure 38. Cumulative weekly COVID-19 vaccine uptake by target group in England

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.

Influenza vaccination

Influenza vaccine uptake in GP patients

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 46 of 2024 (Sunday 17 November 2024), the provisional proportion of people in England who had received an influenza vaccine this season in targeted groups was as follows:

Adults (94.5% of GP practices reporting through Immform):

• 33.4% in those aged under 65 years in a clinical risk group

• 30.1% in all pregnant women

• 68.7% in all those aged over 65 years

Children (93% of GP practices reporting):

• 36.9% in children aged 2 years

• 37.6% in children aged 3 years

Figure 39. Cumulative weekly influenza vaccine uptake by target group in England

On 28 November 2024, monthly data which cover vaccinations that were given between 1 September and 31 October 2024 for GP patients, school-aged children and frontline healthcare workers will be published for the first time 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 in England post-pandemic method report, which uses 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 respdsr.enquiries@ukhsa.gov.uk

Official statistics

Our statistical practice is regulated by the Office for Statistics Regulation (OSR). OSR sets the standards of trustworthiness, quality and value in the Code of Practice for Statistics that all producers of official statistics should adhere to.

You are welcome to contact us directly by emailing respdsr.enquiries@ukhsa.gov.uk with any comments about how we meet these standards.

Alternatively, you can contact OSR by emailing regulation@statistics.gov.uk or via the OSR website.

UKHSA is committed to ensuring that these statistics comply with the Code of Practice for Statistics. This means users can have confidence in the people who produce UKHSA statistics because our statistics are robust, reliable and accurate. Our statistics are regularly reviewed to ensure they support the needs of society for information.