3.1 Episodes of influenza, RSV and COVID-19

During the 2025/26 season, 7,810 influenza episodes were reported, peaking in week 49, 2025 with 1,189 episodes. This was earlier and slightly higher than the previous season’s peak of 1,114 episodes in week 51, 2024 (total in 2024/25: 7,588 episodes) (Figure 1).

RSV activity was lower than the previous season, with 1,796 episodes reported (total in 2024/25: 1,960 episodes). The peak occurred in week 51, 2025 (136 episodes), compared to 218 episodes in week 49, 2024 (Figure 1).

Unlike influenza and RSV, COVID-19 lacks a defined seasonal pattern. During the 2025/26 season, 1,595 episodes were recorded, which peaked in week 40, 2025 (184 episodes). A peak of 205 episodes were reported during the summer in week 38, 2025 (Figure 1). During the 2024/25 season, 1,667 episodes were recorded, which peaked in week 42, 2024 (154 episodes).

During the 2025/26 season, influenza episode rates peaked in the 0–4 age group at 311.4 per 100,000 population in week 49, 2025 followed by the 75+ age group in week 50, 2025 at 130.7 per 100,000. Other age groups showed smaller peaks during the same period in the season. Peak rates were higher in the 0–4 and 5–14 age groups, while rates in the remaining age groups were similar to or lower than those observed in the previous season (Figure 2).

RSV rates were also highest in the 0–4 age group, peaking at 97.0 per 100,000 in week 49, 2025. This peak was lower, but occurred in the same period as that observed in the previous season (148.2 per 100,000 in week 49, 2024). Other age groups reported lower and later peaks than during the 2024/25 season (Figure 2).

For COVID-19, episode rates peaked in the 75+ age group at 53.8 per 100,000 in week 40, 2025, with a late summer peak in the same age group in week 39, 2025 (55.0 per 100,000). In the 2024/25 season, episode rates peaked in the 75+ age group at 48.9 per 100,000 in week 40, 2024. Peak rates were also higher in the 0–4 and 5–14 age groups, while rates in the remaining age groups were generally similar to or lower than those observed in the previous season (Figure 2).

During the 2025/26 season, Derry City and Strabane recorded the highest influenza episode rate in week 49, 2025 (82.0 per 100,000 population), followed by Newry, Mourne and Down in the same week (75.9 per 100,000). The 2025/26 season showed a tendency towards earlier and in several local government districts (LGDs), higher peak activity compared with the previous season, when Mid Ulster reported the highest rate (79.2 per 100,000) in week 51, 2024 (Figure 3).

For RSV, the highest rate was recorded in Derry City and Strabane in week 05, 2025 (14.4 per 100,000), followed by Newry, Mourne and Down in week 48, 2025 (14.2 per 100,000). The 2025/26 season showed generally later and lower peak RSV activity across LGDs compared with the previous season, when the highest rate was observed in Fermanagh and Omagh (22.1 per 100,000) in week 48, 2024 (Figure 3).

COVID‑19 peak rates across LGDs were broadly similar between the 2024/25 and 2025/26 seasons, with peaks generally occurring at a similar time (around weeks 40–42). The highest rate was observed in Mid Ulster in week 40, 2025 (13.8 per 100,00), followed by Armagh City, Banbridge and Craigavon in week 41, 2025 (12.1 per 100,000). The highest rate in the 2024/25 season was observed in Armagh City, Banbridge and Craigavon (14.4 per 100,000) in week 42, 2024 (Figure 3). Mid and East Antrim reported a late summer peak in week 38, 2025 (16.4 per 100,000).

Supplementary tables of unique episodes and weekly episode rates are shown at the end of this report.

3.2 Testing and positivity (%)

During the 2025/26 season, 70,620 influenza tests were conducted, of which 8,137 were positive (11.5%). Of these, 287 were influenza A (H1), 3,054 influenza A (H3), 4,555 influenza A (not subtyped), and 241 influenza B. RSV testing resulted in 1,849 positives from 38,070 tests (4.9%), while SARS‑CoV‑2 testing returned 1,801 positives from 68,156 tests (2.6%).

Influenza positivity peaked at 33.4% in week 49, 2025 (1,232/3,685), earlier and lower than the previous season (35.2% in week 52, 2024). RSV positivity peaked at 9.3% in week 04, 2026 (122/1,309), later and lower to the previous season (17.1% in week 47, 2024). SARS‑CoV‑2 positivity peaked at 10.9% in week 40, 2025 (207/1,896), earlier and lower to the previous season (12.5% in week 42, 2024). SARS‑CoV-2 also saw a late summer peak in week 38, 2025 (12.2%; 216/1,774) (Figure 4).

Shading represents 95% confidence intervals.

During the 2025/26 season, influenza positivity peaked in the 5-14 age group at 57.1% in week 49, 2025 followed by the 15-44 age group in week 48, 2025 at 45.4%, and the 0-4 age group in week 49, 2025 at 44.1%. Older age groups showed smaller peaks during the same period in the season. Peak positivity were lower in the 45-64, 65-74 and 75+ age groups, while positivity in the remaining age groups were similar to the previous season (Figure 5).

RSV positivity was highest in the 0–4 age group, peaking at 37.6% in week 52, 2025. This peak was later and lower than the previous season (54.0% in week 47, 2024). Other age groups reported similar or lower positivity, which peaked later than the previous season (Figure 5).

For COVID-19, positivity peaked in the 5-14 age group at 19.5% in week 06, 2026, with a summer peak in the 0-4 age group in week 32, 2025 (16.9%). In the 2024/25 season, positivity peaked in the 75+ age group at 18.8% in week 40, 2024. Peak positivity were also higher in the 0–4 and 5–14 age groups, while positivity in the remaining age groups were lower than in the previous season (Figure 5).

Supplementary tables of testing and positivity are shown at the end of this report.

Shading represents 95% confidence intervals.

During the 2025/26 season, 13,179 tests for rhinovirus, adenovirus, parainfluenza, and human metapneumovirus were conducted. Of these, 1,816 were positive for rhinovirus (13.8%), 510 for adenovirus (3.9%), 468 for parainfluenza (3.6%), and 437 for human metapneumovirus (3.3%).

Positivity peaked at 21.6% for rhinovirus in week 40, 2025, 6.8% for adenovirus in week 12, 2026, 7.1% for parainfluenza in week 14, 2026, and 8.4% for human metapneumovirus in week 02, 2026. In the 2024/25 season, positivity peaked at 17.0% for rhinovirus in week 41, 2024, 7.5% for adenovirus in week 18, 2025, 9.1% for parainfluenza in week 20, 2025, and 7.5% for human metapneumovirus in week 17, 2025 (Figure 6).

Shading represents 95% confidence intervals.

3.3 Influenza sub-typing

During the 2025/26 season, 7,810 unique influenza episodes were recorded: 261 were typed as influenza A (H1), 2,782 were influenza A (H3), 4,519 were influenza A (not subtyped), and 248 were influenza B (Figure 7). This season was dominated by influenza A (H3), with minimal influenza A (H1) and influenza B activity. In contrast, the previous season saw 7,588 episodes, comprising 2,297 influenza A (H1), 356 influenza A (H3), 3,438 influenza A (not subtyped), and 1,497 influenza B.

A supplementary table of influenza subtyping is shown at the end of this report.

3.4 Sentinel surveillance

Sentinel surveillance plays a role in monitoring and understanding the spread and impact of respiratory viruses like influenza and COVID-19 in the community. It involves a systematic and targeted approach to collect data from a geographical representative subset of GP practices (~15% population representative) to provide information about virus activity across Northern Ireland.

During the 2025/26 season, 423 of 1,136 samples submitted to the Regional Virus Laboratory (RVL) tested positive for influenza (37.2%) (Table 1). Influenza A (H3) was the predominant strain, accounting for 383 positives, followed by 18 influenza A (H1), 17 influenza B, and five influenza A (not subtyped). For RSV, 48 of 1,138 samples were positive (4.2%), and for COVID-19, 28 of 1,060 samples tested positive for SARS-CoV-2 (2.6%) (Table 1).

Total sentinel cases of influenza, RSV and COVID-19 by age group are shown in Figure 8, Figure 9 and Figure 10, and cumulatively for the 2025/26 influenza season in Table 2.

A supplementary table of testing and positivity is shown at the end of this report.

3.5 Non-sentinel surveillance

Non-sentinel surveillance is the monitoring of respiratory viruses from virology data collected from settings such as hospitals and GPs (excluding the sentinel GPs). This provides information about virus activity across Northern Ireland.

During the 2025/26 season, 7,714 of 69,484 samples submitted across laboratories in Northern Ireland tested positive for influenza (11.1%) (Table 3). Influenza A (H3) was the predominant strain, accounting for 2,671 positives, followed by 4,550 influenza A (not subtyped), 269 influenza A (H1) and 224 influenza B. For RSV, 1,801 of 36,932 samples were positive (4.9%), and for COVID-19, 1,773 of 67,096 samples tested positive for SARS-CoV-2 (2.6%) (Table 3).

Total non-sentinel cases of influenza, RSV and COVID-19 by age group are shown in Figure 8, Figure 9 and Figure 13, and cumulatively for the 2025/26 influenza season in Table 4.

A supplementary table of testing and positivity is shown at the end of this report.

3.6 SARS-CoV-2 variants

Unlike influenza and RSV, COVID-19 does not follow a distinct seasonal pattern.

Increased COVID-19 activity was observed during the interseasonal period (week 21 - 39, 2025), with activity remaining low during the 2025/26 season. Among the subset of SARS-CoV-2 positive PCR samples that were sequenced, different prominent variants were identified:

• During the interseasonal period in 2025 (May 19 - September 28), XFG.3 accounted for 25.5% of all samples sequenced with a lineage assigned (114/447), followed by XFG at 23.3% (104/447) (Figure 14).

• During the 2025/26 season (September 29 - May 17), XFG accounted for 34.5% of all samples sequenced with a lineage assigned (142/412) (Figure 14).

Due to small numbers of samples sequenced, the level of confidence in precision of the estimate is low, and the percentages of each variant may change as further results become available.

Parent lineages displayed are subject to change based on lineages under monitoring by the UKHSA horizon scanning team.

A supplementary table of sequenced samples for variants in Northern Ireland during the 2025/26 season is shown at the end of this report.

4.1 Consultation rates for influenza/influenza-like-illness (‘flu/ILI’)

The GP flu/ILI consultation rate exceeded the pre-epidemic threshold for low activity (10.7 per 100,000 population) in week 47, 2025 and remained above baseline for 10 consecutive weeks, returning to baseline in week 05, 2026. The peak consultation rate occurred in week 50, 2025, reaching 57.6 per 100,000 population. This peak was earlier and higher compared to the previous season (week 51, 2024; 49.1 per 100,000) (Figure 15).

By age group, the highest consultation rate was observed in the 0–4 age group in week 50, 2025 (182.8 per 100,000), followed by the 75+ and 5-14 age groups in weeks 51 and 50, 2025, respectively (70.5 and 69.1 per 100,000) (Figure 16).

Regionally, the highest rates were recorded in the Western Trust in week 51, 2025 (92.1 per 100,000), followed by the Southern Trust in week 50, 2025 (68.6 per 100,000) (Figure 17).

Supplementary tables of GP consultation rates are shown at the end of this report.

The baseline MEM threshold for Northern Ireland is <10.7 per 100,000 population for 2025/26. Low activity is 10.7 to <25.8, moderate activity 25.8 to <55.2, high activity 55.2 to <77.1 and very high activity is >77.1 per 100,000 population.

4.2 Consultation rates for acute respiratory infection (ARI)

The highest ARI consultation rate during the 2025/26 season was recorded in week 51, 2025, at 281.1 per 100,000 population. The timing of this peak was consistent with previous seasons. However, this peak was lower with subsequent weeks rates closely aligning with the previous season (Figure 18).

By age group, consultation rates were consistently highest among the 0–4 age group, peaking in week 49, 2025, at 1,280.1 per 100,000 (Figure 19).

Regionally, the highest rates were recorded in the Western Trust in week 51, 2025 (423.9 per 100,000), followed by the Belfast Trust in the same week (280.0 per 100,000) (Figure 20).

Supplementary tables of GP consultation rates are shown at the end of this report.

4.3 Consultation rates for COVID-19

Unlike influenza and RSV, COVID-19 does not follow a distinct seasonal pattern.

Increasing COVID-19 consultation rates were observed during the interseasonal period (week 21 - 39, 2025), with rates declining and remaining low during the 2025/26 season. The highest rate during the 2025/26 season was recorded in week 40, 2025, at 5.1 per 100,000 population. Rates over the previous two seasons remain lower than the peaks recorded during the COVID-19 pandemic (Figure 21).

By age group, consultation rates were consistently highest among the 0–4 age group, peaking in week 49, 2025, at 1,280.1 per 100,000 (Figure 19).

Regionally, the highest rates were recorded in the South Eastern Trust in week 40, 2025 (6.6 per 100,000), followed by the Southern Trust in week 41, 2025 (5.2 per 100,000) (Figure 23).

Supplementary tables of GP consultation rates are shown at the end of this report.

5.1 Influenza, RSV and COVID-19 care homes outbreaks

During the 2025/26 season, a higher number of respiratory outbreaks in care homes (95) were reported to the PHA Health Protection Acute Response Duty Room compared with the previous season (80). This increase may be associated with the predominance of influenza A (H3), alongside minimal influenza A (H1) activity. Seasons dominated by influenza A (H3) are typically associated with higher numbers of care home outbreaks and increased hospital admissions among older adults (Figure 24).

Of these, five were confirmed as influenza A (H3), 62 as influenza A (not subtyped), nine as RSV, 17 as COVID-19, and two as co-circulating influenza A (not subtyped) and RSV outbreaks in care home settings. The highest number of outbreaks occurred in week 49, 2025, when 14 outbreaks were reported: 12 influenza A (not subtyped), one influenza A (H3) and one RSV (Figure 24).

A supplementary table detailing confirmed care home outbreaks is provided at the end of this report.

6.1 Admissions and occupancy

During the 2025/26 season, total community-acquired emergency respiratory admissions were lower than in the previous season, with 3,866 admissions recorded compared to 4,198. This season was characterised by an earlier and lower peak, primarily driven by influenza A admissions (2,429), with substantially fewer influenza B admissions later in the season (68). RSV admissions (832) were also lower than in the previous season, while COVID-19 admissions (537) remained broadly similar (Figure 25).

Admissions began to increase in week 44, 2025, peaking in week 49, 2025 with 408 admissions. Of these, 348 were attributable to influenza A, 42 to RSV and 18 to COVID-19. From week 13, 2025, influenza B admissions surpassed those of influenza A. Unlike the previous season, RSV admissions did not exhibit a distinct peak but instead showed a more prolonged plateau with a gradual decline. COVID-19 admissions remained low throughout the season, consistent with the previous season (Figure 25).

Age-specific admission rates showed that the 75+ age group had the highest influenza admission rate, peaking in week 51, 2025 at 63.5 per 100,000 population. This was followed by the 0–4 age group, which peaked in week 50, 2025 at 60.6 per 100,000. Compared with the previous season, the peak in the 75+ age group was lower, while the peak in the 0–4 age group was higher. RSV admission rates were highest in the 0–4 age group, peaking in week 51, 2025 at 54.1 per 100,000. This peak was lower than that observed in the previous season. COVID-19 admission rates peaked in the 75+ age group in week 41, 2025 at 20.8 per 100,000 (Figure 26).

Supplementary tables of community-acquired emergency hospital admissions are shown at the end of this report.

Inpatient occupancy mirrored these trends. Influenza A inpatients peaked in late December 2025, occurring at a similar time but at a lower level than the peak observed in the previous season. Influenza B activity was later in the season and remained lower overall in 2025/26. RSV inpatients did not exhibit a distinct peak, instead showing a more prolonged plateau followed by a gradual decline. COVID-19 inpatient trends were similar, remaining relatively low and without a clear peak, following a period of elevated inpatient levels during summer 2025 (Figure 27).

Community-acquired emergency respiratory inpatient trends varied considerably by age group, with the highest burden observed in older adults. The 75+ age group experienced the largest peak, driven predominantly by influenza A in late December 2025. This peak occurred at a similar time to the previous season but at a lower level. Adults aged 45–64 and 65–74 showed similar seasonal patterns, although with lower overall numbers, largely attributable to influenza A. The 5–14 and 15–44 age groups had comparatively low inpatient numbers throughout the 2025/26 season, consistent with the previous season. In contrast, the 0–4 age group displayed an earlier peak, driven largely by RSV with some contribution from influenza A. However, overall inpatient numbers in this age group remained substantially lower than those observed in the 75+ age group (Figure 28).

7.1 Deaths related to influenza and/or pneumonia

NISRA death statistics are published weekly. These statistics report on deaths where influenza and/or pneumonia was mentioned anywhere on the death certificate. As a result, the counts will reflect deaths where influenza or pneumonia has contributed to a death but was not necessarily the underlying cause of the death.

During the 2025/26 season, there were 2,198 deaths involving influenza and/or pneumonia out of 11,726 total registered deaths (18.7%). This proportion is similar to the previous season, which saw 2,230 such deaths out of 11,688 registered (19.1%). The proportion of influenza and/or pneumonia related deaths peaked in week 52, 2025, when 28.6% of all registered deaths involved influenza and/or pneumonia (Figure 29).

7.2 Deaths related to COVID-19

NISRA death statistics report on deaths where COVID-19 was mentioned anywhere on the death certificate. As a result, the counts will reflect deaths where COVID-19 has contributed to a death but was not necessarily the underlying cause of the death.

During the 2025/26 season, 67 COVID-19 related deaths were reported out of 11,726 total registered deaths (0.6%). This is a slight decrease from the previous season, which saw 97 such deaths out of 11,688 registered (0.8%). The proportion of COVID-19 related deaths peaked in week 41, 2025, when 2.9% of all registered deaths involved COVID-19. This proportion remained between ~0–1% throughout the remainder of the 2025/26 season (Figure 30).

7.3 Excess Mortality

NISRA use the UK-wide methodology to report on excess deaths as advised by the Office for National Statistics (ONS).

EuroMOMO is a European mortality monitoring activity, aiming to detect and measure excess deaths related to seasonal influenza, pandemics and other public health threats. During the current 2025/26 season, excess mortality has been reported in weeks 48 and 50, 2025, and weeks 01 and 03, 2026. Reports on excess deaths across Europe and the United Kingdom are published weekly.

9.1 Feedback and contact information

To provide feedback and for all queries relating to this document, please contact FluSurveillance@hscni.net.

9.2 Acknowledgements

Compiled by the Respiratory Surveillance Team, Health Protection Surveillance, Public Health Agency with contributions from:

• PHA Health Protection duty room
• Vaccines Surveillance Team
• Data Science Team
• PHA Communications Team
• Regional Virus Laboratory (RVL) and Trust laboratories
• Health and Social Care Trusts including Northern Ireland
• Sentinel GP Network
• Trust consultants and nurses
• Northern Ireland Statistics and Research Agency (NISRA)
• EuroMOMO Hub
• Queen’s University Belfast

10.1 Presentation of data

Unless otherwise stated, data are presented using epidemiological weeks (a standardised method of counting weeks [Monday-Sunday] to allow for the comparison of data year after year). This is dependent on the data available. The data included in this report are the most up to date data available at the time of the report; however, this is subject to change as the data are subject to ongoing quality assurance.

10.2 Virology surveillance

All virology data provided here are preliminary. Virology data for prior weeks, as included in this or future reports, are subject to updates based on laboratory returns received after the last report was produced. The report offers the most up-to-date information available.

Rates per 100,000 population are calculated using the NISRA 2024 Mid-Year Population Estimates.

10.3 SARS-CoV-2 genomics

A subset of SARS-CoV-2 positive PCR samples are sent to sequencing laboratories in Belfast Health and Social Care Trust and Queen’s University Belfast for sequencing. On 29th November 2022 the lineage assignment algorithm was switched from PangoLEARN to UShER for lineage counts. PangoLEARN uses a machine learning algorithm, whereas UShER uses phylogenetic placement and produces fewer unassigned lineages. This switch has been applied retrospectively, therefore total counts for all lineages have been affected.

10.4 Primary care surveillance

Consultation rates for influenza/influenza-like-illness (‘flu/ILI’), acute respiratory infection (ARI) and COVID-19

GP in-hours consultation data with ~95% coverage of the Northern Ireland population is auto-extracted weekly from the General Practitioner Intelligence Platform (GPIP). This data includes weekly aggregate consultations for ‘flu/ILI’, ARI, and COVID-19, and includes weekly registered patients. The data is available for different Health and Social Care Trusts, and by age and sex.

10.5 Community surveillance

Care home outbreaks

PHA conducts surveillance of outbreaks across multiple settings, including care homes (nursing homes and residential homes) in Northern Ireland that are registered with the Regulation and Quality Improvement Agency (RQIA). All care homes have a requirement to notify the PHA Health Protection duty room of suspected outbreaks of any infectious disease. A confirmed outbreak of influenza, RSV or COVID-19 is defined as where there are two or more confirmed cases with onset within a 14 day period, where transmission within the care home facility is considered the likely cause.

10.6 Secondary care surveillance

Influenza and RSV

Community-acquired influenza and RSV emergency admissions to acute hospitals are estimated by combining data from the Patient Administration System (PAS), EPIC and virological reports in the Northern Ireland Health Analytics Platform (NIHAP). Admissions are counted where there was a positive test up to seven days before admission or up to one day after admission, and the method of admission was ‘Emergency’. The number of inpatients is counted at midnight. Admissions and occupancy refer to the first admission per infection episode.

COVID-19

Community-acquired COVID-19 emergency admissions to acute hospitals are estimated by combining data from the PAS, EPIC and virological reports in NIHAP. Admissions are counted where there was a positive PCR or lateral flow test up to 14 days before admission or up to one day after admission., and the method of admission was ‘Emergency’. The number of inpatients is counted at midnight. Admissions and occupancy refer to the first admission per infection episode. The method used in this report is different to that previously reported by the Department of Health’s COVID-19 dashboard, which used administrative coding to identify COVID-19 admissions.

10.7 Mortality surveillance

NISRA death statistics are published weekly, and include weekly counts of deaths related to influenza and/or pneumonia (new from 31 January 2025), and deaths related to COVID-19. This enables comparisons with weekly information published by the Office for National Statistics (ONS) covering England and Wales.

The statistics report on deaths where influenza and/or pneumonia, or COVID-19, was mentioned anywhere on the death certificate. As a result, the counts will reflect deaths where these diseases have contributed to a death but was not necessarily the underlying cause of the death.

11.1 Unique episodes of influenza, RSV and COVID-19, by epidemiological week, week 40 - week 20, 2025/26

11.2 Influenza, RSV and COVID-19 episode rates per 100,000 population, by age group, week 40 - week 20, 2025/26

11.3 Influenza, RSV and COVID-19 episode rates per 100,000 population, by local government district, week 40 - week 20, 2025/26