2.1 Episodes of influenza, RSV and COVID-19

The number of new influenza episodes increased in week 45, with 212 unique episodes identified. There were 135 episodes reported in week 44. There were 39 new RSV episodes identified in week 45, higher to week 44 when 23 episodes were identified (Figure 2.1).

Influenza and RSV episode rates by age groups are shown in (Figure 2.2). The highest influenza episode rate in week 45 was in 0-4 age group (39.8 per 100,000 population). The highest RSV episode rate in week 45 was also in the 0-4 age group (31.0 per 100,000 population).

Influenza and RSV episode rates across local government districts (LGD) are shown in (Figure 2.3). Mid and East Antrim had the highest influenza episode rate in week 45 (17.3 per 100,000 population). Lisburn and Castlereagh had the highest RSV episode rate in week 45 (4.0 per 100,000 population).

The number of new COVID-19 episodes decreased in week 45, with 45 unique episodes identified. There were 53 episodes reported in week 44 (Figure 2.1).

COVID-19 episode rates by age groups are shown in (Figure 2.2). The highest COVID-19 episode rate in week 45 was in the 75+ age group (13.9 per 100,000 population).

COVID-19 episode rates across LGD are shown in (Figure 2.3). Derry City and Strabane and Lisburn and Castlereagh had the highest COVID-19 episode rate in week 45 (both 4.0 per 100,000 population).

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

Figure 2.1: Weekly number of unique episodes of influenza, RSV and COVID-19 by epidemiological week

Figure 2.2: Weekly episode rates of influenza, RSV and COVID-19 per 100,000 population, by age group and epidemiological week

Figure 2.3: Weekly episode rates of influenza, RSV and COVID-19 per 100,000 population, by local government district and epidemiological week

2.2 Testing and positivity (%)

In week 45 there were 2,064 influenza tests, 215 of which were positive (10.4% positivity). This is an increase from week 44 (7.6% positivity) (Figure 2.4). Influenza positivity in week 45 was highest in the 5-14 age group (30.6% positivity) (Figure 2.5).

There were 1,118 RSV tests, 39 of which were positive (3.5% positivity). This is an increase from week 44 (2.5% positivity) (Figure 2.4). RSV positivity in week 45 was highest in the 0-4 age group (17.8% positivity) (Figure 2.5).

There were 1,747 COVID-19 tests, 53 of which were positive (3.0% positivity). This is slightly lower to week 44 (3.3% positivity) (Figure 2.4). COVID-19 positivity in week 45 was highest in the 75+ age group (4.6% positivity) (Figure 2.5).

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

Figure 2.4: Weekly positivity for influenza, RSV and COVID-19, by epidemiological week

Shading represents 95% confidence intervals.

Figure 2.5: Weekly positivity for influenza, RSV and COVID-19, by age group and epidemiological week

Shading represents 95% confidence intervals.

In week 45 there were 338 rhinovirus tests, 48 of which were positive (14.2% positivity). This is a decrease from week 44 (17.2% positivity) (Figure 2.6).

There were 338 adenovirus tests, 13 of which were positive (3.9% positivity). This is a small increase from week 44 (3.3% positivity) (Figure 2.6).

There were 338 parainfluenza tests, 11 of which were positive (3.3% positivity). This is similar to week 44 (3.3% positivity) (Figure 2.6).

There were 338 human metapneumovirus (hMPV) tests, nine of which were positive (2.7% positivity). This is an increase from week 44 (0.9% positivity) (Figure 2.6).

Figure 2.6: Weekly positivity for rhinovirus, adenovirus, parainfluenza and Human metapneumovirus, by year and epidemiological week

Shading represents 95% confidence intervals.

2.3 Influenza sub-typing

Of the 212 new influenza episodes identified in week 45, four were typed as Flu A (H1), 73 were Flu A (H3), 132 were Flu A (not subtyped) and three were Flu B (Figure 2.7).

A supplementary table of influenza sub-typing is shown at the end of this report.

Figure 2.7: Weekly number of unique episodes of influenza, by subtype and epidemiological week

2.4 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 NI.

In week 45, six samples were positive for influenza from 29 samples submitted for testing to the Regional Virus Laboratory (RVL) (20.7% positivity). One sample was typed as Flu A (H1), three were Flu A (H3) and two were Flu A (not subtyped). No samples were positive for RSV. For COVID-19, one sample was positive (3.6% positvity from 28 samples submitted for testing (Table 1).

Total sentinel cases of influenza, RSV and COVID-19 by age group for the previous year are shown in (Figure 2.8), (Figure 2.9) and (Figure 2.10), 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.

Figure 2.8: Weekly sentinel influenza cases, by age group and epidemiological week

Figure 2.9: Weekly sentinel RSV cases, by age group and epidemiological week

Figure 2.10: Weekly sentinel COVID-19 cases, by age group and epidemiological week

2.5 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 NI.

In week 45, 209 samples were positive for influenza from 2,035 samples submitted for testing to laboratories across NI (10.3% positivity). Of these, five were typed as Flu A (H1), 73 were Flu A (H3), 130 were Flu A (not subtyped) and one was Flu B. For RSV, 39 samples were positive from 1,089 samples submitted for testing (3.6% positivity). For COVID-19, 52 samples were positive from 1,719 samples submitted for testing (3.0% positivity) (Table 3).

Total non-sentinel cases of influenza, RSV and COVID-19 by age group for the previous year are shown in (Figure 2.8), (Figure 2.9) and (Figure 2.13), 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.

Figure 2.11: Weekly non-sentinel influenza cases, by age group and epidemiological week

Figure 2.12: Weekly non-sentinel RSV cases, by age group and epidemiological week

Figure 2.13: Weekly non-sentinel COVID-19 cases, by age group and epidemiological week

2.6 SARS-CoV-2 variants

In the 8 weeks 01 September 2025 to 26 October 2025, 292 COVID-19 samples were sequenced. Of these, 106 were XFG (36.3% of all sequenced samples), 80 were XFG.3 (27.4% of all sequenced samples), 38 were NB.1.8.1 (13.0% of all sequenced samples), 18 were LP.8.1 (6.2% of all sequenced samples), 7 were BA.3 (2.4% of all sequenced samples), 6 were BA.2 (2.1% of all sequenced samples), 5 were KP (1.7% of all sequenced samples) and 3 were JN.1 (1.0% of all sequenced samples) 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.A more detailed COVID-19 Genomics Bulletin containing a further breakdown of sub-lineages is published weekly.

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

Figure 2.14: Total number of sequenced variants of COVID-19 by Pangolin lineage, by epidemiological week

Recombinant refers to any recombinant lineage, starting “X”, that does not fall under the parent lineage of a defined variant.

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3.1 Influenza, RSV and COVID-19 care homes outbreaks

Two COVID-19 outbreaks were reported in week 45. One occurred in a care home and the other in an assisted living facility. In week 44 there were no outbreaks reported (Figure 3.1).

Figure 3.1: Weekly number of confirmed influenza, RSV and COVID-19 outbreaks, by epidemiological week

4.1 Admissions and occupancy

There were 94 new community-acquired emergency hospital admissions during week 45 (Figure 4.1). Of these, 59 were Flu A, 25 were RSV and 10 were COVID-19. This is an increase from week 44 (87 admissions).

Community-acquired emergency hospital admission rates in week 45 were highest in the 0-4 and 75+ age groups for influenza (8.8 and 8.6 respectively per 100,000 population), the 0-4 age group for RSV (20.4 per 100,000 population), and the 75+ age group for COVID-19 (2.6 per 100,000 population) (Figure 4.2).

Supplementary tables of emergency hospital admissions and rates by age group are shown at the end of this report.

Community-acquired emergency influenza admissions have risen, while RSV admissions have seen a slight increase but continue to remain low. For COVID-19, community-acquired emergency admissions have decreased (Figure 4.3).

Figure 4.1: Weekly number of community-acquired emergency influenza, RSV and COVID-19 hospital admissions, by epidemiological week

Figure 4.2: Weekly community-acquired emergency influenza, RSV and COVID-19 hospital admission rates per 100,000 population, by age group and epidemiological week

Figure 4.3: Influenza, RSV and COVID-19 community acquired emergency inpatients, by day

5.1 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.

The latest data is available for week ending 31 October 2025. In week 44, 59 influenza and/or pneumonia related deaths from 322 deaths were reported (18.3%). This is higher to the previous week with 40 influenza and/or pneumonia related deaths from 283 deaths were reported (14.1%) (Figure 5.1).

Figure 5.1: Weekly deaths and percentage of registered deaths related to influenza and/or pneumonia, to most recent registration week

5.2 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.

The latest data is available for the week ending 31 October 2025. In week 44, four COVID-19 related deaths from 322 deaths were reported (1.2%). This is higher to the previous week with one COVID-19 related death from 283 deaths were reported (0.4%) (Figure 5.2).

Figure 5.2: Weekly deaths and percentage of registered deaths related to COVID-19, to most recent registration week

5.3 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. Reports on excess deaths across Europe and the United Kingdom are published weekly.

7.1 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.

7.2 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 current report offers the most current information available.

Rates per 100,000 population are calculated using the NISRA 2021 Mid-Year Population Estimates.

7.3 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 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. A more detailed COVID-19 Genomics Bulletin containing a further breakdown of sub-lineages is published weekly.

7.4 Community surveillance

Care home outbreaks

PHA conducts surveillance of outbreaks across multiple settings, including care homes (nursing homes and residential homes) in NI 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 can be 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.

7.5 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 from 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. The number of inpatients is counted at midnight. Admissions and occupancy refer to the first admission per infection episode, including transfers between hospitals. 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.

7.6 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.

8.1 Unique episodes of influenza, RSV and COVID-19, by epidemiological week, over a six week period

8.2 Influenza, RSV and COVID-19 episode rates per 100,000 population, by age group, over a six week period

8.3 Influenza, RSV and COVID-19 episode rates per 100,000 population, by local government district, over a six week period

8.4 Total tests and positivity for influenza, RSV and COVID-19, by epidemiological week, over a six week period

8.5 Positivity for influenza, RSV and COVID-19, by age group and epidemiological week, over a six week period

8.6 Unique episodes of influenza, by subtype, over a six week period

8.7 Total sentinel tests and positivity for influenza, RSV and COVID-19, by epidemiological week, over a six week period

8.8 Total non-sentinel tests and positivity for influenza, RSV and COVID-19, by epidemiological week, over a six week period

8.9 Number of sequenced samples for variants in Northern Ireland

This table only shows counts for lineages with 10 or more sequenced samples from 2024 - 45 onwards. Lineage counts include provisional and confirmed sequencing samples. Lineage calls are subject to change following analysis of genomic sequence results, which may result in fluctuations in lineage counts.

8.10 Number of community-acquired emergency hospital admissions, over a six week period

8.11 Community-acquired emergency hospital admission rates per 100,000 population, by age group, over a six week period