Official Statistics

National flu and COVID-19 surveillance report: 17 April 2025 (week 16)

Updated 17 April 2025

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 15 of 2025 (between 7 April and 13 April 2025).

Main points

The main messages of this report are:

• influenza activity decreased across most indicators and was at baseline levels
• COVID-19 showed mixed activity across indicators and was circulating at baseline levels
• respiratory syncytial virus (RSV) activity decreased across indicators and was circulating at baseline levels

Give your feedback

We are asking for feedback on the National weekly influenza and COVID-19 surveillance report. We want to learn more about how you use this report, what areas you find valuable and where you would suggest improvements. Your feedback will help shape future reports. This feedback form will be open until 22 May 2025.

Summary of all respiratory virus activity

Influenza activity

Influenza activity decreased across most indicators and was at baseline activity levels. Emergency department (ED) attendances for influenza-like-illness (ILI) continued to decrease overall. The number of influenza-confirmed acute respiratory infections (ARI) incidents in week 15 remained stable compared with the previous week.

This season, so far influenza A(H1N1) has been the predominant subtype detected. The proportion of influenza B increased in 2025. There have also been a small number of influenza A(H3N2) detections.

Reporting of weekly influenza vaccine uptake for the 2024 to 2025 season concluded in week 6.

Indicator	Trend	Level [note 1]	Comments
Laboratory surveillance	Decreasing	Low	Influenza positivity decreased with a weekly mean positivity rate of 5.3% compared with 6.2% in the previous week
ILI general practice (GP) consultations	Decreasing	Baseline	The weekly ILI consultation rate decreased to 4 per 100,000 registered population in participating GP practices compared with 4.8 per 100,000 in the previous week
GP swabbing positivity	Decreasing	Baseline	In week 14, among all tested samples, 7.2% were positive for influenza, compared with 11.9% in the previous week
Hospital admissions	Increasing	Baseline	The overall weekly hospital admission rate for influenza increased to 1.57 per 100,000 compared with 1.40 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 0.03 per 100,000 compared with 0.05 per 100,000 in the previous week

Note 1: these indicators use the moving epidemic method (MEM) and the mean standard deviation method (MSD) to define thresholds to determine their respective levels of activity. Further information on these methods can be found in Influenza surveillance in Europe: establishing epidemic thresholds by the Moving Epidemic Method and 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 some influenza surveillance indicators, however, for other indicators both the MEM and MSD are experimental and may be subject to future revision. Influenza laboratory surveillance (from week 1) and GP swabbing positivity (from week 2) have transitioned from using MEM to using MSD. These approaches will be considered alongside expert opinion and triangulation of other data sources.

COVID-19 activity

COVID-19 showed mixed activity across indicators and was circulating at baseline levels. ED attendances for COVID-19-like remained stable. The number of reported SARS-CoV-2 confirmed acute respiratory infections (ARI) incidents in week 15 remained stable compared with the previous week.

In sequenced samples, the most prevalent lineage was XEC.

Indicator	Trend	Level [note 2]	Comments
Laboratory surveillance	Stable	Baseline	COVID-19 PCR (polymerase chain reaction) positivity in hospital settings remained stable with a weekly mean positivity rate of 4.9% compared with 4.7% in the previous week
GP swabbing positivity	Increasing	Baseline	In week 14, among all tested samples, 3.6% were positive for SARS-CoV-2, compared with 1.7% in the previous week
Hospital admissions	Decreasing slightly	Baseline	The overall weekly hospital admission rate for COVID-19 slightly decreased to 1.33 per 100,000 compared with 1.47 per 100,000 in the previous week
ICU/HDU admissions	Stable	Baseline	The overall ICU or HDU rate for COVID-19 remained stable at 0.02 per 100,000 compared with 0.05 per 100,000 in the previous week

Note 2: these indicators use the 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 indicators and was circulating at baseline levels overall. ED attendances for acute bronchiolitis decreased.

Reporting of weekly RSV hospital admissions for the 2024 to 2025 season concluded in week 14.

Indicator	Trend	Level [note 1]	Comments
Laboratory surveillance	Decreasing	Baseline	RSV positivity decreased to 0.7% compared with 1.2% in the previous week.
GP swabbing positivity	Decreasing	Baseline	In week 14, among all tested samples, 0.7% were positive for RSV compared with 1.5% in the previous week

Note 1: these indicators use the 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	Increasing	Medium	Adenovirus positivity (laboratory surveillance) increased to 5.3% compared with 3.7% in the previous week
Human metapneumovirus (hMPV)	Stable	Medium	hMPV positivity (laboratory surveillance) remained stable at 4.7% compared with 4.4% in the previous week
Parainfluenza	Increasing	Medium	Parainfluenza positivity (laboratory surveillance) increased to 4.8% compared with 3.7% in the previous week
Rhinovirus	Stable	Baseline	Rhinovirus positivity (laboratory surveillance) remained stable at 11.5% compared with 11.2% in the previous week

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 MEM and the 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 15 April 2025, there were a total of 1,056 COVID-19 cases identified in hospital settings in week 15, decreasing slightly from 1,170 cases in the previous week. COVID-19 PCR positivity in hospital settings remained stable in week 15, with a weekly average positivity rate of 4.9% compared with 4.7% in the previous week. Positivity rates were highest in those aged 85 years and over at a weekly average positivity rate of 7.8%. This remained stable when compared with week 14, when positivity rates were at 7.5% 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 15 April 2025, influenza positivity in week 15 decreased with a weekly average positivity rate of 5.3% compared with 6.2% in the previous week. Influenza positivity rates were highest in those aged between 25 and 44 years at a weekly average positivity rate of 12.4%. This has decreased from 14.3% among those aged between 25 and 44 years in week 14.

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 15, data is based on reporting from 9 out of the 14 sentinel laboratories.

In week 15, 5,564 respiratory specimens reported through the Respiratory DataMart System were tested for influenza. There were 237 positive samples for influenza: 99 influenza A (not subtyped), 36 influenza A (H3N2), 14 influenza A (H1N1)pdm09, and 88 influenza B. Overall, influenza positivity decreased slightly to 4.3% in week 15 compared with 5.2% in the previous week.

In week 15, 5,282 respiratory specimens reported through the Respiratory DataMart System were tested for SARS-CoV-2. There were 183 positive samples for SARS-CoV-2. SARS-CoV-2 positivity increased slightly to 3.5% compared with 3.2% in the previous week, with the highest positivity in those aged 80 years and over at 5.2%.

RSV positivity decreased to 0.7%, with the highest positivity in those aged under 5 years at 1.3%.

Adenovirus positivity increased to 5.3%, with the highest positivity in those aged under 5 years at 15.6%.

Human metapneumovirus (hMPV) positivity remained stable at 4.7%, with the highest positivity in those aged under 5 years at 10%.

Parainfluenza positivity increased to 4.8%, with the highest positivity in those aged under 5 years at 12.4%.

Rhinovirus positivity remained stable at 11.5%, with the highest positivity in those aged under 5 years at 32.1%.

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

This section is updated fortnightly. Data below was last updated in the week 15 report.

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 3 March 2025 and 16 March 2025. Of those sequenced in this period 26.47% were classified as XEC, 19.12% were classified as LP.8.1.1, 13.24% were classified as JN.1, 13.24% were classified as JN.1.11.1, 10.29% were classified as KP.3.1.1 and 5.88% were classified as MC.1. Note that low sequencing numbers will impact the accuracy of the prevalence estimates.

Please note that lineages will be grouped independently from their parent lineage once they reach sufficient prevalence, and may be re-grouped into their parent lineage if their prevalence subsequently falls. 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 1 April 2024 to 23 March 2025

Influenza virus characterisation

Between week 40 2024 (week ending 1 September 2024) and week 15 2025 (week ending 13 April 2025), the UKHSA respiratory virus unit (RVU) has genetically characterised 2178 seasonal influenza viruses, and identified 313 influenza A(H3N2) viruses, 1090 influenza A(H1N1)pdm09 viruses and 775 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. RVU have also characterised one influenza A(H5N1) virus.

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	A/Netherlands/10468/2023	1015
A	H1N1	5a.2a.1	D.3	Not assigned yet	63
A	H1N1	5a.2a.1	D.5	Not assigned yet	7
A	H1N1	5a.2a.1	D.1	Not assigned yet	4
A	H1N1	5a.2a.1	D	A/Victoria/4897/2022	1	A/Victoria/4897 is the (H1N1)pdm09 component of the 2024/2025 NH egg-based vaccine
A	H3N2	2a.3a.1	J.2	A/Sydney/878/2023	243
A	H3N2	2a.3a.1	J.2.2	A/Lisboa/216/2023	48
A	H3N2	2a.3a.1	J.1.1	A/Canberra/331/2023	10
A	H3N2	2a.3a.1	J.2.1	A/West Virginia/51/2024	9
A	H3N2	2a.3a	G.1.3.1	Not assigned yet	2
A	H3N2	2a.3a.1	J	A/Thailand/8/2022	1	A/Thailand/8/2022 is the H3N2 component of the 2024/2025 NH egg-based vaccine
A	H5N1	2.3.4.4b	DI	A/Greylag_Goose/England/141175/2024	1
B	Victoria	V1A.3a.2	C.5.1	B/Catalonia/2279261NS/2023	328
B	Victoria	V1A.3a.2	C.5.6	B/Brisbane/145/2023	276
B	Victoria	V1A.3a.2	C.5.7	B/SouthAustralia/78/2023	154
B	Victoria	V1A.3a.2	C.5	B/Connecticut/01/2021	15
B	Victoria	V1A.3a.2	C.3	B/Moldova/2030521/2023	2

UKHSA RVU performs antigenic characterisation of influenza A(H1N1)pdm09, influenza A(H3N2) and influenza B viruses using haemagglutination inhibition (HI) assays. Data from these assays are used to compare how similar the currently circulating influenza viruses are to the strains included in seasonal influenza vaccines, and to monitor for changes in circulating influenza viruses. Similarity of currently circulating influenza strains to vaccine strains is defined as having an antibody titre within 4-fold when compared to reference viruses representative of the vaccine strain.

Influenza virus antigenic characterisation

• A(H1N1)pdm09: 145 A(H1N1)pdm09 viruses have been antigenically characterised and 145 (100%) were similar to reference viruses representative of the A/Victoria/4897/2022 (H1N1)pdm09‑like Northern Hemisphere 2024/25 (H1N1)pdm09 vaccine strain
• A(H3N2): 57 A(H3N2) viruses have been antigenically characterised and 46 (81%) were similar to reference viruses representative of the A/Thailand/8/2022 (H3N2)‑like Northern Hemisphere 2024/25 (H3N2) vaccine strain
• B/Victoria: 39 influenza B viruses have been antigenically characterised and 39 (100%) were similar to reference viruses representative of the B/Austria/1359417/2021 (B/Victoria lineage)‑like Northern Hemisphere 2024/25 influenza B vaccine strain

Influenza virus antiviral susceptibility surveillance

Influenza positive samples are screened for mutations in the virus neuraminidase and the cap-dependent endonuclease of the polymerase acidic protein 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	1052	2	15
H1N1pdm09	Zanamivir	1068	1	0
H3N2	Oseltamivir	298	0	0
H3N2	Zanamivir	298	0	0
B/Victoria	Oseltamivir	764	2	0
B/Victoria	Zanamivir	762	4	0
H5N1	Oseltamivir	1	0	0
H5N1	Zanamivir	1	0	0

• Patient 1: 1 influenza A(H1)pdm09 positive sample with H275Y detected. Immune compromised adult patient known to have received oseltamivir treatment

• Patient 2: 1 influenza A(H1)pdm09 positive sample with H275Y detected. Immune compromised adult patient known to have received oseltamivir treatment

• Patient 3: 1 influenza A(H1)pdm09 positive sample with H275Y detected. Immunocompetent patient with preexisting severe lung disease and known to have received oseltamivir treatment

• Patient 4: 1 influenza A(H1)pdm09 positive sample with H275Y detected. Immune compromised adult patient not known to have received oseltamivir treatment

• Patient 5: 1 influenza A(H1)pdm09 positive sample with H275Y detected. Immune compromised adult patient known to have received oseltamivir treatment

• Patient 6: 1 influenza A(H1)pdm09 positive sample with I427T detected. Immunocompetent adult patient known to have not receive oseltamivir treatment

• Patient 7: 1 influenza A(H1)pdm09 positive sample with I223M detected. Immunocompetent infant who did not receive oseltamivir treatment

• Patient 8: 1 influenza A(H1)pdm09 positive sample with H275Y detected. Immune compromised adult patient known to have received oseltamivir treatment

• Patient 9: 1 influenza A(H1)pdm09 positive sample with H275Y detected. Immune compromised adult patient known to have received oseltamivir treatment

• Patient 10: 1 influenza A(H1)pdm09 positive sample with H275Y detected. Immune compromised adult patient known to have received oseltamivir treatment

• Patient 11: 1 influenza B positive sample with T146K detected. Immunocompetent adult patient who did not receive oseltamivir treatment. T146K has been identified as having a weak association with reduced susceptibility to Oseltamivir and Zanamivir, however the clinical implications are unclear due to lack of available information

• Patient 12: 1 influenza A(H1)pdm09 positive sample with H275Y detected. Immune compromised adult patient known to have received oseltamivir treatment

• Patient 13: 1 influenza A(H1)pdm09 positive sample with H275Y detected. Immune compromised adult patient, did not receive oseltamivir treatment

• Patient 14: 1 influenza B positive sample with G407S detected. Immunocompetent adult patient, did not receive oseltamivir treatment

• Patient 15: 1 influenza A(H1)pdm09 positive sample with H275Y detected. Immune compromised adult patient known to have received oseltamivir treatment

• Patient 16: 1 influenza A(H1)pdm09 positive sample with H275Y detected. Immune compromised adult patient known to have received oseltamivir treatment

• Patient 17: 1 influenza A(H1)pdm09 positive sample with H275Y detected. Immune compromised adult patient known to have received oseltamivir treatment

• Patient 18: 1 influenza B positive sample with G145R detected. Adult patient with preexisting medical condition known to have received oseltamivir treatment

• Patient 19: 1 influenza A(H1)pdm09 positive sample with H275Y detected. Immunocompetent adult patient, exposure to antiviral drugs unknown at the time of publication of this report

• Patient 20: 1 influenza B positive sample with N294S detected. Immunocompetent adult patient who did not receive oseltamivir treatment

• Patient 21: 1 influenza A(H1)pdm09 positive sample with H275Y detected. Information on immune status and exposure to antiviral drugs is unknown at the time of publication of this report

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	763	0
H3N2	292	0
B/Victoria	752	0
H5N1	1	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 57 new ARI incidents reported in week 15 in England. These included:

• 54 incidents from care homes, of which 9 were due to SARS-CoV-2, 8 were due to influenza A, 5 were due to multiple pathogens, 3 were due to other pathogens, 2 were due to influenza (no type information available), 2 were due to influenza B and 1 was due to RSV

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

• no incidents from educational settings

• no incidents from prisons

• no incidents from other settings

Figure 11. Number of ARI incidents by setting, England

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

FluSurvey

Community surveillance using FluSurvey ended for the 2024 to 2025 season in week 15 2025 and will resume next season. No further 2024 to 2025 season data will be included in this report.

Flu Detector

We are pausing the reporting of Flu Detector whilst we investigate an issue with the data source indicated by an unusual pattern in the data in recent weeks.

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 13 April 2025, ED attendances for acute respiratory infection decreased and were similar to seasonally expected levels. ED attendances for influenza-like illness continued to decrease and were above seasonally expected levels. ED attendances for COVID-19-like illness remained stable. ED attendances for acute bronchiolitis, a syndrome related to RSV infection, decreased and were similar to seasonally expected levels.

Daily NHS 111 calls for acute respiratory infections decreased. NHS 111 online assessments for acute respiratory infection decreased. GP out-of-hours contacts for acute respiratory infections decreased and were similar to seasonally expected levels.

Figure 13a. 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 13b. 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 14a. 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 14b. 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 15a. 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 15b. 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 16a. 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 16b. 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 decreased to 4 per 100,000 registered population in participating GP practices in week 15 compared with 4.8 per 100,000 in the previous week. This rate is in the baseline activity level (Figure 17). By age group, the highest rates were seen in those aged under 1 year (7.5 per 100,000), followed by those aged 75 and over years (5.8 per 100,000).

The lower respiratory tract infections (LRTI) consultation remained stable at 79.8 per 100,000 in week 15 compared with 81.2 per 100,000 in the previous week.

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

Figure 17. 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

226 samples were taken in week 15 through the GP sentinel swabbing, and 11 tested positive (Figure 18). 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 120 tested samples in week 15, 1.7% were positive for SARS-CoV-2, 0.8% for influenza, 0% for RSV, 5% for adenovirus, and 1.7% for hMPV (Figure 19). 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 18. 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 19. Percentage of detected respiratory virus among all samples with completed testing in England by week, GP sentinel swabbing scheme [note 11] [note 12]

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 viruses among all samples with completed testing in England by age group, GP sentinel swabbing scheme, week 12 to week 15 [note 12]

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

Figure 21. Weekly positivity for SARS-CoV-2, influenza and RSV in England, GP sentinel swabbing scheme

Secondary care surveillance

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 15 2025 based on 87 NHS trusts in England were as follows:

• the overall weekly hospital admission rate for COVID-19 slightly decreased to 1.33 (compared with 1.47 per 100,000 in the previous week)

• hospital admission rates for COVID-19 were highest in the London region (remained stable at 2.18 per 100,000 compared with 2.19 in the previous week). Please refer to the supplementary graphs and data file for regional breakdowns

• the highest hospital admission rate for COVID-19 was in those aged 85 years and over (remained stable at 14.02 per 100,000 compared with 14.46 in the previous week)

COVID-19 ICU-HDU admissions in week 15 2025 based on 71 NHS trusts in England were as follows:

• the overall ICU or HDU rate for COVID-19 remained low at 0.02 per 100,000 (compared with 0.05 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 North West region (remained low at 0.09 per 100,000 compared with 0.05 in the previous week). Please refer to the supplementary graphs and data file for regional breakdowns

• the highest ICU or HDU admission rate for COVID-19 was in those aged between 75 and 84 years (decreasing to 0.11 per 100,000 compared with 0.19 in the previous week)

Figure 22. Weekly overall COVID-19 hospital admission rates per 100,000 trust catchment population reported through SARI Watch mandatory surveillance, England [note 13]

Note 13: please note that a correction has been made to 2020 week numbers.

Figure 23. 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 24. Weekly overall COVID-19 ICU or HDU admission rates per 100,000 trust catchment population reported through SARI Watch mandatory surveillance, England [note 13]

Note 13: please note that a correction has been made to 2020 week numbers.

Figure 25. 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 15 2025 based on 23 sentinel NHS trusts in England were as follows:

• the overall weekly hospital admission rate for influenza increased to 1.57 per 100,000 (compared with 1.40 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 85 years and over (6.87 per 100,000). Please refer to the supplementary graphs and data file for regional breakdowns

• there were 173 new hospital admissions for influenza (92 influenza A(not subtyped), 2 influenza A(H1N1)pdm09, 1 influenza A(H3N2), and 78 influenza B)

Influenza ICU-HDU admissions in week 15 2025 based on 94 NHS trusts in England were as follows:

• the overall ICU or HDU rate for influenza remained low at 0.03 per 100,000 (compared with 0.05 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 supplementary graphs and data file for regional breakdowns

• there were 14 new ICU or HDU admissions for influenza (7 influenza A(not subtyped), 2 influenza A(H1N1)pdm09, 0 influenza A(H3N2), and 5 influenza B)

Figure 26. Weekly overall influenza hospital admission rates per 100,000 trust catchment population with MEM thresholds, reported through SARI Watch sentinel surveillance, England [note 14]

Note 14: please note that a correction has been made to 2019 week numbers.

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

Figure 28. Weekly hospital admission rate by age group for new influenza reported through SARI Watch sentinel surveillance, England [note 6] [note 15]

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

Note 15: 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 29. 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 14]

Note 14: please note that a correction has been made to 2019 week numbers.

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

Figure 31. Weekly ICU or HDU admission rate by age group for new influenza cases, reported through SARI Watch mandatory surveillance, England [note 6] [note 15]

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

Note 15: 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 surveillance paused at week 14 for the 2024 to 2025 season. We will be including retrospective updates to week 14 2025 inclusive in the last edition of the national weekly report for the 2024 to 2025 season to be published on 22 May 2025.

RSV hospitalisations, excluding ICU or HDU admissions, in week 14 2025 based on 19 sentinel NHS trusts in England were as follows:

• the overall weekly hospital admission rate for RSV decreased to 0.18 per 100,000 (compared with 0.27 per 100,000 in the previous week)

• in children aged under 5 years, the hospitalisation rate for RSV decreased to 0.76 per 100,000 (compared with 1.78 per 100,000 in the previous week)

• in adults aged 75 years and over, the hospitalisation rate for RSV increased to 1.45 per 100,000 (compared with 0.99 per 100,000 in the previous week). Broken down further, rates were 0.90 per 100,000 in those aged between 75 and 84 years, and 2.87 per 100,000 in those aged 85 years and over in week 14

Figure 32. Weekly hospital admission rates (excluding ICU or HDU) of RSV positive cases per 100,000 population reported through SARI Watch sentinel surveillance, England [note 13] [note 16]

Note 13: please note that a correction has been made to 2020 week numbers.

Note 16: 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 33. 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 16]

Note 16: 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 count of hospital admissions of RSV positive cases reported through SARI Watch sentinel surveillance by level of care, England

Figure 35. Weekly hospital admission rates (excluding ICU or HDU) by age group for RSV cases reported through SARI Watch sentinel surveillance, England [note 6] [note 17]

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

Note 17: 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 no new ECMO admissions (any cause) reported in week 15 2025 in adults.

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 36. 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 15 2025 (Sunday 13 April 2025) 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 reporting week (Monday 14 April 2025). 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.

Spring 2025 campaign

The Spring 2025 data reported below covers any dose administered from 1 April 2025 (ISO Week 14) 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 15 2025 (week ending 13 April 2025) 26.2% of all people aged 75 years and over, and 2.2% of all people aged under 75 years and in a clinical risk group, who are living and resident in England had been vaccinated with a Spring 2025 dose since 1 April 2025 (Figure 37).

Figure 37. Cumulative weekly COVID-19 vaccine uptake by target group in England [note 18]

Note 18: 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.

Since the 19 December 2024, monthly data for frontline healthcare workers has been published. This covers vaccinations that were given between 1 September 2024 and 28 February 2025 and is available under the joint flu and COVID-19 vaccine uptake report.

Influenza vaccination coverage

On 27 March, monthly data which cover vaccinations that were given between 1 September and 28 February 2025 for GP patients and frontline healthcare workers was published. 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.

This was the last monthly publication of the 2024 to 2025 season. Final end of season annual reports for GP patients, frontline healthcare workers and school-aged children will be published on 22 May 2025.

Influenza vaccine uptake in GP patients

For GP patients up to 28 February 2025, the provisional proportion of people in England who had received an influenza vaccine this season in targeted groups was as follows:

Main survey (98.7% of GP practices reporting through ImmForm):

• 40.0% in those aged under 65 years in a clinical risk group
• 35.0% in all pregnant women
• 74.9% in those aged 65 years and over

Children’s survey (99.2% of GP practices reporting):

• 41.7% in children aged 2 years
• 43.5% in children aged 3 years

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

Influenza vaccine uptake in frontline healthcare workers

On 27 March, 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 28 February 2025. Based on an 82.8% response rate national vaccine uptake is 37.9%. 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 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.