Integrated Respiratory Virus Bulletin, Ireland

Week 4 2026 (starting from 25/01/2026)

Report prepared on 05/02/2026



This interactive bulletin reports on the latest epidemiology of COVID-19, influenza, respiratory syncytial virus (RSV) and other respiratory viruses (ORVs) in Ireland. HPSC monitors several integrated respiratory virus surveillance systems that are included in this bulletin. This report will be published weekly during the winter season (week 40 to week 20).

How to use this interactive bulletin

For interactive graphs – data values and labels can be seen by hovering over graph lines or bars. Specific categories can be selected or deselected by clicking on the relevant category in the legend. Readers can skip to specific sections by clicking on the table of contents to the left of the screen.

Please note: data based on notifications follow the epidemiological calendar, with the week beginning Sunday, while other surveillance systems follow the international ISO calendar where the week begins on Monday. Unless otherwise stated, data figures and tables in this report follow the epidemiological calendar. Because the 2025 epidemiological calendar includes a week 53 and the ISO calendar does not, week labels throughout 2026 will differ according to the calendar used.


1 Key messages

Influenza activity decreased across most surveillance indicators and was at low levels overall; activity peaked in weeks 50–51, 2025. RSV activity stabilised and remained at moderate levels overall. COVID-19 activity stabilised overall and was at low levels.

Vaccination/immunisation remains one of the most effective ways to reduce severe illness from influenza, RSV, and COVID-19. Strong surveillance, immunisation programmes, and healthcare system readiness (including Infection Prevention Control) are key to protecting public health.

1.1 Summary for most recent week

Syndromic surveillance

The sentinel GP Acute Respiratory Infection (ARI) consultation rate decreased further in ISO week 5 2026, following the peak in week 50 2025. The ARI rate was at moderate levels at 109/100,000 population during week 5. The highest rate was in those aged 0-4 years at 468.7/100,000 population. The sentinel GP influenza-like-illness (ILI) consultation rate decreased in recent weeks and was at low levels at 22.8/100,000 population during week 5. Sentinel GP influenza test positivity was at low levels in recent weeks at 16% for week 5. Sentinel GP human metapneumovirus (hMPV) test positivity was also at low levels at 11.9%. SARS-CoV-2, RSV and all other seasonal respiratory pathogens’ test positivity levels were below the 10% baseline threshold. The percentage of GP Out-Of-Hours (GP-OOH) calls for self-reported flu and cough calls decreased; flu calls were below the baseline threshold for the first time since week 46 2025, cough calls remained above the baseline threshold for week 5.

COVID-19

COVID-19 activity remained stable and was at low levels overall in week 4 2026. The overall incidence was 3.2/100,000 population, and highest in those aged <1 year. COVID-19 cases increased by 14%, from 146 cases in week 3 to 167 in week 4. Emergency Department (non-hospitalised) COVID-19 cases increased by 28% from 60 in week 3 to 77 in week 4. Hospitalisations decreased by 8% from 52 cases in week 3 to 48 cases in week 4. There have been 23 ICU admissions and 78 deaths reported for this season to date. COVID-19 hospital bed occupancy remained stable during recent weeks. XFG remained the predominant SARS-CoV-2 variant, accounting for 90% of samples sequenced between weeks 42 and 46 2025. A total of 11 variant under monitoring (VUM) BA.3.2 sequences have been detected to date in Ireland.

Influenza

Influenza activity decreased across most surveillance indicators in week 4 2026 and was at low levels overall. Influenza activity peaked during weeks 50–51 2025. The overall incidence was 13.3/100,000 population and highest in those aged ≥80 years. Influenza cases decreased by 24%, from 899 cases in week 3 to 685 cases in week 4. Emergency Department (non-hospitalised) influenza cases decreased by 25%, from 462 in week 3 to 348 in week 4. Hospitalisations decreased by 39%, from 277 cases in week 3 to 138 cases in week 4. There have been 171 ICU admissions and 181 deaths reported for this season to date. Influenza hospital bed occupancy decreased in recent weeks. Influenza A(H3) accounted for the majority of subtyped influenza A viruses during the season to date. Of influenza A(H3N2) samples sequenced by the National Virus Reference Laboratory to date, the majority belonged to the new subclade K (Clade 2a.3a.1; former J.2.4.1). 

RSV

RSV activity stabilised and remained at moderate levels overall. The overall incidence was 10.5/100,000 population and highest in those aged <1 year. RSV cases decreased by 4%, from 568 cases in week 3 to 543 cases in week 4. Emergency Department (non-hospitalised) RSV cases increased by 6% from 181 in week 3 to 191 in week 4. Hospitalisations decreased by 18% from 199 cases in week 3 to 164 cases in week 4. There have been 59 ICU admissions and 15 deaths reported for the season to date. RSV hospital bed occupancy remained low and stable last week.

Severe Acute Respiratory Infection (SARI)

In ISO week 5 2026, SARI activity remained stable and at moderate levels in Ireland; 112 SARI cases were reported from all four sentinel hospital sites. In week 5 influenza test positivity decreased for the second consecutive week to 8%, RSV test positivity decreased to 18% and SARS-CoV-2 test positivity increased slightly to 3%.

Outbreaks

There were 52 acute respiratory infection (ARI) outbreaks notified in health and care settings during week 4 2026 (five COVID-19, 23 influenza, 13 RSV and 11 other ARI), and remained stable compared to the 55 ARI outbreaks reported during week 3. Of the 52 ARI outbreaks, 13 were in hospitals, 19 were in nursing homes, 12 were in residential institutions, seven were in community hospital/long-stay units and one was in another healthcare service.

Excess mortality

The latest HPSC excess mortality analysis of all registered deaths in Ireland up to February 1st, 2026 (ISO week 5 2026) using the standardised European EuroMOMO algorithm shows that overall excess all-cause mortality was reported for the entire Irish population (all ages) most recently in week 2 2026, and also in week 50 2025 and week 52 2025. In addition, excess pneumonia and influenza related mortality was observed for six weeks, in week 50 2025 and in the period from week 52 2025 to week 4 2026.


2 Syndromic and case surveillance

2.1 Sentinel GP Acute Respiratory Infection (ARI) and Influenza-like-illness (ILI) surveillance

2.1.1 Sentinel GP ARI and ILI

1: Sentinel GP ARI and ILI consultation rates per 100,000 population overall (with associated number of influenza, RSV and SARS-CoV-2 positive sentinel GP ARI specimens) in Ireland, from week 40 2024 to week 5 2026. Data source: Sentinel GP surveillance system and National Virus Reference Laboratory (NVRL). Note: week number follows the ISO calendar


2.1.2 Sentinel GP ARI by age group

2: Sentinel GP ARI consultation incidence by age-group in Ireland, from week 40 2024 to week 5 2026. Data source: Sentinel GP surveillance system. Note: week number follows the ISO calendar


2.2 GP out-of-hours surveillance


3: Percentage of calls to GP out-of-hours services for self-reported cough and self-reported influenza in Ireland for all ages and by age-group, by week of call, from week 40 2024 to week 5 2026. Data source: Participating GP Out-of-Hours services in Ireland. Note: week number follows the ISO calendar


2.3 Confirmed cases

2.3.1 Laboratory-confirmed cases: COVID-19, influenza, RSV

4: Number of notified cases of laboratory-confirmed COVID-19, influenza and RSV by week of notification in Ireland, between week 40 2024 and week 4 2026. Data source: CIDR



2.3.2 COVID-19 seasonal trends

5: Number of notified cases of laboratory-confirmed COVID-19 by week of notification in Ireland, between week 40 2022 and week 4 2026. Data source: CIDR

Please note: where there is a 53 week year, the average of week 52 and week 53 is taken. The week labelled week 52 2025 in Figures 5, 6 and 7 have a total number of confirmed cases which is the average of the total for weeks 52 and 53 2025


2.3.3 Influenza seasonal trends

6: Number of notified cases of laboratory-confirmed influenza by week of notification in Ireland, between week 40 2022 and week 4 2026. Data source: CIDR

Please note: where there is a 53 week year, the average of week 52 and week 53 is taken. The week labelled week 52 2025 in Figures 5, 6 and 7 have a total number of confirmed cases which is the average of the total for weeks 52 and 53 2025


2.3.4 RSV seasonal trends

7: Number of notified cases of laboratory-confirmed RSV by week of notification in Ireland, between week 40 2022 and week 4 2026. Data source: CIDR

Please note: where there is a 53 week year, the average of week 52 and week 53 is taken. The week labelled week 52 2025 in Figures 5, 6 and 7 have a total number of confirmed cases which is the average of the total for weeks 52 and 53 2025


Table 1: Number and incidence of notified laboratory-confirmed cases of COVID-19, influenza and RSV by age, sex and HSE Health Region Ireland, week 4 2026. Data source: CIDR

Number of cases (incidence per 100,000 population)

All pathogens

COVID-19

Influenza

RSV

Cases

1,395 (27.1)

167 (3.2)

685 (13.3)

543 (10.5)

Age groups (years)

<1

125 (216.3)

20 (34.6)

28 (48.4)

77 (133.2)

1-4

224 (94.3)

27 (11.4)

65 (27.4)

132 (55.6)

5-14

95 (13.3)

22 (3.1)

43 (6.0)

30 (4.2)

15-44

200 (9.7)

32 (1.5)

125 (6.0)

43 (2.1)

45-64

173 (13.4)

21 (1.6)

95 (7.3)

57 (4.4)

65-79

276 (46.4)

26 (4.4)

164 (27.5)

86 (14.4)

≥80

302 (166.8)

19 (10.5)

165 (91.1)

118 (65.2)

Median age (IQR)

52 (4-77)

31 (3-66)

63 (23-79)

40 (1-77)

Sex

Male

650 (25.5)

75 (2.9)

327 (12.9)

248 (9.7)

Female

742 (28.5)

91 (3.5)

358 (13.7)

293 (11.2)

HSE Health Regions

Dublin and North East

349 (29.4)

43 (3.6)

206 (17.4)

100 (8.4)

Dublin and Midlands

242 (22.5)

30 (2.8)

111 (10.3)

101 (9.4)

Dublin and South East

284 (29.2)

35 (3.6)

116 (11.9)

133 (13.7)

South West

132 (17.8)

13 (1.8)

64 (8.6)

55 (7.4)

Mid West

77 (18.6)

5 (1.2)

38 (9.2)

34 (8.2)

West and North West

307 (40.4)

40 (5.3)

149 (19.6)

118 (15.5)


An overview of the characteristics of all cases reported since the start of the season is presented in Appendix A1.


Figure 8: Incidence of influenza and RSV notified cases by week of notification in Ireland for the 2025/2026 season with comparison to the 2024/2025 season, thresholds (baseline-very high) are defined using the Moving Epidemic Method. Data source: CIDR

Further details on the Moving Epidemic Method can be found in the Technical notes.


9: Incidence of notified cases of laboratory-confirmed COVID-19, influenza and RSV by HSE Health Region for the last 12 weeks by week of notification, from week 46 2025 to week 4 2026. Data source: CIDR


10: Age and sex-specific incidence of notified cases of laboratory-confirmed COVID-19, influenza and RSV in Ireland, from week 40 2025 to week 4 2026. Data source: CIDR

Please note that the scale on the x-axis may differ by pathogen, to account for differences in the number of cases notified for each pathogen.


11: Incidence of notified cases of laboratory-confirmed COVID-19, influenza and RSV in Ireland, by age group and week of notification, from week 40 2024 to week 4 2026. Data source: CIDR


3 Severity and impact

3.1 Sentinel Severe Acute Respiratory Infection (SARI) surveillance

3.1.1 SARI case numbers by site

12: Number of SARI hospitalised cases by ISO week of hospital admission in Ireland, from week 40 2025 to week 5 2026. Data source: Sentinel SARI surveillance system. Note: week number follows the ISO calendar

Note: In ISO weeks 41,49,52 2025 and weeks 2 & 3 one or more SARI hospital sites did not report data.

3.1.2 Incidence of SARI hospital admissions

13: SARI age-specific incidence rates per 1,000 hospital admissions by ISO week of hospital admission in Ireland, from week 40 2025 to week 5 2026. Data source: Sentinel SARI surveillance system. Note: week number follows the ISO calendar

*SARI cases are recruited from emergency department admissions only in SVUH, SJH and UHL. In CHI-C cases are recruited from emergency department and non-emergency department routes (e.g. transfer from other hospitals, direct admission to speciality wards), excluding day cases and elective admissions.

Note: In ISO weeks 41,49,52 2025 and weeks 2 & 3 2026 one or more SARI hospital sites did not report data.


14: Percentage of SARI cases with a positive laboratory test result for SARS-CoV-2, influenza or RSV by ISO week of hospital admission in Ireland, from week 40 2025 to week 5 2026. Data source: Sentinel SARI surveillance system. Note: week number follows the ISO calendar

Note: In ISO weeks 41,49,52 2025 and weeks 2 & 3 2026 one or more SARI hospital sites did not report data.


3.2 Emergency department cases

3.2.1 Incidence of emergency department cases

15: Incidence of emergency department cases of laboratory-confirmed COVID-19, influenza and RSV by week of notification in Ireland, from week 40 2024 to week 4 2026. Data source: CIDR


3.2.2 Number of emergency department cases


16: Number of emergency department cases of laboratory-confirmed COVID-19, influenza and RSV by week of notification in Ireland, from week 40 2024 to week 4 2026. Data source: CIDR


3.3 Hospital admissions

3.3.1 Incidence of hospitalised cases


17: Incidence of hospitalised cases of laboratory-confirmed COVID-19, influenza and RSV by week of notification in Ireland, from week 40 2024 to week 4 2026. Data source: CIDR


3.3.2 Number of hospitalised cases


18: Number of hospitalised cases of laboratory-confirmed COVID-19, influenza and RSV by week of notification in Ireland, from week 40 2024 to week 4 2026. Data source: CIDR


Table 2: Number and incidence of hospitalised cases of laboratory-confirmed COVID-19, influenza and RSV by age, sex and HSE Health Region Ireland, week 4 2026. Data source: CIDR

Number of cases (incidence per 100,000 population)

All pathogens

COVID-19

Influenza

RSV

Cases

350 (6.8)

48 (0.9)

138 (2.7)

164 (3.2)

Age groups (years)

<1

31 (53.6)

4 (6.9)

4 (6.9)

23 (39.8)

1-4

57 (24.0)

8 (3.4)

10 (4.2)

39 (16.4)

5-14

25 (3.5)

7 (1.0)

6 (0.8)

12 (1.7)

15-44

35 (1.7)

8 (0.4)

15 (0.7)

12 (0.6)

45-64

41 (3.2)

7 (0.5)

20 (1.5)

14 (1.1)

65-79

69 (11.6)

7 (1.2)

38 (6.4)

24 (4.0)

≥80

92 (50.8)

7 (3.9)

45 (24.9)

40 (22.1)

Median age (IQR)

61 (4-80)

31 (4-69)

71 (41-82)

36 (1-78)

Sex

Male

173 (6.8)

22 (0.9)

77 (3.0)

74 (2.9)

Female

177 (6.8)

26 (1.0)

61 (2.3)

90 (3.5)

HSE Health Regions

Dublin and North East

44 (3.7)

9 (0.8)

23 (1.9)

12 (1)

Dublin and Midlands

37 (3.4)

5 (0.5)

15 (1.4)

17 (1.6)

Dublin and South East

73 (7.5)

11 (1.1)

20 (2.1)

42 (4.3)

South West

47 (6.3)

4 (0.5)

19 (2.6)

24 (3.2)

Mid West

40 (9.7)

3 (0.7)

20 (4.8)

17 (4.1)

West and North West

105 (13.8)

15 (2)

40 (5.3)

50 (6.6)


An overview of the characteristics of all hospitalised cases reported since the start of the season is presented in Appendix A2.


19: Age and sex-specific incidence of hospitalised cases of laboratory-confirmed COVID-19, influenza and RSV in Ireland, from week 40 2025 to week 4 2026. Data source: CIDR

Please note that the scale on the x-axis may differ by pathogen, to account for differences in the number of cases notified for each pathogen.


20: Incidence of hospitalised cases of laboratory-confirmed COVID-19, influenza and RSV by age group in Ireland, from week 40 2024 to week 4 2026. Data source: CIDR


3.3.3 Bed occupancy in acute inpatient settings

3.3.3.1 Number of acute hospital beds occupied last 30 days

21: Daily number of acute hospital beds occupied by patients with laboratory-confirmed COVID-19, influenza and RSV in Ireland in the last 30 days. Data source: HSE Planning and Performance Unit


3.3.3.2 Number of acute hospital beds occupied week 40, 2024 onwards

22: Daily number of acute hospital beds occupied by patients with laboratory-confirmed COVID-19, influenza and RSV in Ireland from week 40 2024 to week 5 2026. Note: week number follows the ISO calendar. Data source: HSE Planning and Performance Unit


3.4 Intensive Care Unit (ICU) admissions


23: Number of ICU admissions due to laboratory-confirmed COVID-19, influenza and RSV by week of admission to ICU in Ireland, week 40 2024 to week 4 2026. Data source: CIDR


Table 3: Number and incidence of ICU admissions due to COVID-19, influenza and RSV in Ireland by week of admission to ICU, week 4 2026, and season to date (from week 40 2025 to week 4 2026). Data source: CIDR

Week 4, 2026

Week 40, 2025 to week 4, 2026

Number of ICU admissionsa

ICU admissions per 1,000 hospitalisations

% of hospitalised cases admitted to ICU

Number of ICU admissions

ICU admissions per 1,000 hospitalisations

% of hospitalised cases admitted to ICU

COVID-19

0

0

0

23

16.6

1.7

Influenza

0

0

0

171

31.5

3.1

RSV

0

0

0

59

31.8

3.2

aICU admissions include all cases admitted to ICU due to COVID-19, influenza and RSV


3.5 Mortality

3.5.1 Deaths among confirmed cases


24: Number of COVID-19, influenza and RSV deaths by week of death in Ireland, week 40 2024 to week 4 2026. Data source: CIDR


Table 4: Number and incidence of COVID-19, influenza and RSV deaths in Ireland, for the season to date (from week 40 2025 to week 4 2026). Data source: CIDR

COVID-19

Influenza

RSV

Age (years)

Number of deaths

Incidence per 100,000 population

Number of deaths

Incidence per 100,000 population

Number of deaths

Incidence per 100,000 population

<65

5

0.1

18

0.4

0

0.0

≥65

73

9.4

163

21.0

15

1.9

Total

78

1.5

181

3.5

15

0.3


4 Outbreaks


25: Number of COVID-19, influenza, RSV and other ARI outbreaks reported in health and care settings by week outbreak reported in Ireland, from week 40 2024 to week 4 2026. Data source: CIDR


Table 5: Number of COVID-19, influenza, RSV and other ARI outbreaks reported by setting in Ireland, week 4 2026 and the season to date (from week 40 2025 to week 4 2026). Data source: CIDR

Week 4 2026

Outbreak location

COVID-19

Influenza

RSV

ARI

Total week 4, 2026

Total week 40, 2025 to week 4, 2026

Comm. hosp/long-stay unit

1

3

2

1

7

59

Hospital

1

9

3

0

13

242

Nursing home

0

8

7

4

19

340

Other healthcare service

0

0

0

1

1

13

Residential institution

3

3

1

5

12

83

Total health care settings

5

23

13

11

52

737

Total non health care settings

0

0

0

0

0

6

Total

5

23

13

11

52

744


26: Number of COVID-19, influenza, RSV and other ARI outbreaks by HSE Health Region, Ireland week 4 2026. Data source: CIDR


5 Virology and genomic surveillance

5.1 Virus test positivity and dominant virus types/subtypes in circulation


Table 6: Number and percentage positive SARS-CoV-2, influenza and RSV specimens by surveillance source Ireland, week 5 2026. Data source: NVRL. Note: week number follows the ISO calendar

SARS-CoV-2

Influenza

RSV

Surveillance system

Total tested

Total positive

% positive

Total positive

% positive

Total positive

% positive

NVRL Sentinel GP ARI

67

3

4.5

11

16.4

5

7.5

NVRL non-sentinel respiratory

32

2

6.2

3

9.4

2

6.2


27: Sentinel GP ARI specimens and non-sentinel respiratory specimen test positivity for SARS-CoV-2, influenza, RSV and other respiratory viruses by week of specimen collection in Ireland, week 21 2025 to week 5 2026. PIV = parainfluenza viruses. Data source: NVRL. Note: week number follows the ISO calendar


28: Number of sentinel GP ARI and non-sentinel respiratory influenza positive specimens and laboratory-confirmed influenza notifications by influenza type/sub-type and by week of specimen collection in Ireland, week 40 2024 to ISO week 5 2026 / Epi week 4 2026. Data source: NVRL, CIDR


Underlying data on the total number of tests, total number of positives and percentage positive by week and for the season to date for each virus for both sentinel and non-sentinel specimens are presented in Appendix A3, Appendix A4, Appendix A5, Appendix A6


5.2 SARS-CoV-2 genomic data


29: SARS-CoV-2 whole genome sequencing results by week of specimen collection in Ireland, from week 40 2024 to week 46 2025


Note: There is typically a lag time of 1-3 weeks between a case being notified, selected for sequencing and sequencing being completed. This may be longer when there is a lower number of cases due to batching of specimens. Therefore, the percentage of cases notified in this time period who are ultimately sequenced will be higher than reported here.


30: SARS-CoV-2 whole genome sequencing results by week of specimen collection in Ireland, from week 42 2025 to week 46 2025


6 SARS-CoV-2 wastewater surveillance


31: Approximate location of wastewater catchment areas and SARS-CoV-2 viral loads (gc/day) in wastewater and percentage change compared to previous week, National Wastewater Surveillance Programme Ireland, week 3 2026


Figure 32: Weekly distribution of population-normalised SARS-CoV-2 viral load (gc/day/person), National Wastewater Surveillance Programme Ireland, May 2021 to week 3 2026


9 Technical notes

General

Data are provisional and subject to ongoing review, validation and update. As a result, figures in this report may differ from previously published figures.

Data for epiweeks 53 2025 - week 2 2026 should be interpreted with caution as surveillance data are impacted during the Christmas/New Year holiday period, due to changes in reporting, testing and associated changes with healthcare provision and healthcare seeking behaviour. Data for these weeks may not accurately reflect the epidemiological situation.

The weekly calendar runs from Sunday to Saturday for respiratory virus notifications on CIDR (as per the Infectious Disease Regulations 1982 and subsequent amendments) and Monday to Sunday for the sentinel GP and SARI surveillance systems (as per ISO week). Further information on epidemiological dates and weeks can be found on the HPSC website.

Please note that the excess mortality data are provisional due to the time delay with death registration in Ireland. A country-specific adjustment function was applied to correct for the typical delay in registrations of deaths in Ireland. Nonetheless, estimates of excess mortality for the most recent weeks are reported with some uncertainty and should be interpreted with caution.

Definitions

The case definitions for COVID-19, influenza and RSV are available here. Only data on laboratory-confirmed cases, including cases diagnosed using near patient molecular tests, are included in this report.

Sentinel GP ARI consultations are consultations to sentinel GP practices for Acute Respiratory Infection (ARI), with ARI defined as Sudden onset of symptoms AND at least one of the following four respiratory symptoms: Cough, sore throat, shortness of breath, coryza AND a clinician’s judgement that the illness is due to an infection.

Sentinel GP ILI consultations are consultations to sentinel GP practices for Influenza like illness (ILI), with ILI defined as Sudden onset of symptoms AND at least one of the following four respiratory symptoms: Fever or feverishness, malaise, headache, myalgia AND at least one of the following three respiratory symptoms: Cough, sore throat, shortness of breath.

GP out of hours calls refer to calls to GP out of hours services from persons with self-reported clinical symptoms of ‘flu’ or ‘cough’.

Emergency Department cases refer to cases treated in emergency departments, with no indication on CIDR that they have subsequently been admitted to hospital.

Hospitalised cases are inpatients with laboratory-confirmed SARS-CoV-2, influenza or RSV and includes inpatients with incidental infections, where the infection is not the reason for their admission.

Bed occupancy refers to the number of laboratory-confirmed cases admitted to acute inpatient sites at 08:00 hrs on the day of reporting.

A SARI case is defined as a person hospitalised for at least 24 hours with acute respiratory infection and onset of symptoms within 14 days prior to hospital admission, with at least one of the following symptoms: cough, fever, shortness of breath OR sudden onset of anosmia, ageusia or dysgeusia.

The case definition was adapted in Ireland for infants aged <6 months to include increased work of breathing and apnoea as relevant symptoms, the revised definition was applied to cases admitted from week 40 2025. A SARI case refers to an individual patient episode of care.

As of September 2024, ICU admissions for COVID-19, influenza and RSV refer to those admitted to intensive care where COVID-19, influenza or RSV were the primary or contributory cause of admission. Prior to September 2024, ICU admissions for influenza and RSV included all admissions where the patient tested positive for influenza or RSV, irrespective of whether these pathogens were the cause of admission.

COVID-19, influenza and RSV deaths are defined as a death in a person with laboratory-confirmed COVID-19, influenza or RSV infection. see case definitions (this includes cases detected postmortem)

Moving Epidemic Method (MEM) thresholds have been established to assess the intensity of respiratory virus activity. Thresholds have been calculated using five years of historical notification data from 2017/2018 to 2024/2025. The seasons 2020/2021 and 2021/2022 were excluded, due to low influenza and RSV in circulation during the COVID-19 pandemic. SARS-CoV-2 has a bimodal epidemic pattern and therefore is unsuitable for threshold analysis using the MEM. Further details

Test Positivity: Positive tests refer to all positive specimens and includes duplicates and individuals who were re-tested.

Outbreaks are defined as two or more cases of acute respiratory infection with the same pathogen (SARS-CoV-2, influenza or respiratory syncytial virus (RSV)) confirmed by a laboratory test or near patient test carried out by a health professional, and where there is reason to consider that these cases may be epidemiologically linked in place and time.

Other Acute Respiratory Infection (ARI) outbreaks are defined as: Two or more cases of acute respiratory infection arising within the same 48hr period epidemiologically linked in place: Outbreaks are classified as Suspect ARI outbreaks, where testing has not been completed, is pending or has been negative for Influenza, RSV and SARS-CoV-2. Outbreaks are classified as confirmed if other respiratory pathogens (ORVs), e.g. Rhinovirus, hMPV, Coronavirus OC43 etc are identified via laboratory confirmation. The outbreak data presented in this report includes both confirmed and suspect outbreaks.

Variant working definitions for ‘SARS-CoV-2 variants of concern’ (VOC), ‘SARS-CoV-2 variants of interest’ (VOI) and ‘SARS-CoV-2 variants under monitoring’ (VUM) are available on the WHO website and ECDC website.

Data sources

The Computerised Infectious Disease Reporting (CIDR) system: CIDR is the source of statutory notification data on laboratory-confirmed COVID-19, influenza, RSV (including data on notified, emergency department, hospitalised and ICU cases and data on cases who died) and data on outbreaks.

The type/subtype of laboratory-confirmed influenza notifications are reported on the CIDR system. The number of cases hospitalised and admitted to ICU described in this report relate only to cases notified during this reporting period, with known hospitalisation/ICU status at the time of reporting.

Regional Departments of Public Health currently prioritise the investigation and reporting of outbreaks in settings that benefit most from public health and clinical intervention. The outbreak data reported here focuses on these key settings/groups. These settings include acute hospitals, nursing homes, community hospital/long-stay units, residential institutions (centres for disabilities, centres for older people, children’s/TUSLA residential centres and mental health facilities) and other healthcare settings.

Population denominator data for analyses of CIDR data on notified, emergency department, hospitalised and ICU cases and deaths are taken from Census 2022.

Sentinel GP surveillance system: This includes 100 participating general practices (located in all HSE Health Regions). These practices report electronically on a weekly basis, the number of patients who consulted with acute respiratory infection (ARI) and influenza-like illness (ILI) (identified using International Classification of Primary Care 2 codes R74 and R80). These practices provide overall and age-stratified denominator data on the number of registered patients who have sought care at the practice during the previous three years. The combined patient population in these practices is estimated to be approximately 10% of the national population. Sentinel GPs take a combined nose and throat swab from the first five patients attending their practice each week who meet the ARI case definition and send these to the NVRL for testing.

GP Out-of-hours (GPOOHs) services: Five out of 14 GPOOHs services provide weekly data on the total and age-stratified number of out of hours calls for 1) all reasons, 2) for self-reported cough and 3) for self-reported flu. The denominator for calculations of percentage of calls is the total number of calls for all reasons.

The HSE Performance Management and Improvement Unit (PMIU) provides daily data on bed occupancy (the number of currents inpatients with laboratory-confirmed COVID-19, influenza and RSV).

Severe Acute Respiratory Infections (SARI) surveillance system: SARI cases are identified based on clinical symptoms from new admissions through the Emergency Department in SVUH, SJH and UHL. In CHI-C cases are recruited from emergency department and non-emergency department routes (e.g. transfer from other hospitals, direct admission to speciality wards), excluding day cases and elective admissions.

National Virus Reference Laboratory (NVRL): The NVRL routinely test sentinel GP and non-sentinel respiratory specimens for SARS-CoV-2, influenza, RSV and a panel of other seasonal respiratory viruses (ORV). The NVRL report on influenza type/subtype of sentinel GP ARI and non-sentinel respiratory specimens on a weekly basis.

The SARS-CoV-2 genomic sequencing sampling framework currently focuses on notified COVID-19 cases with severe disease (hospitalisation, ICU admission) and deaths, COVID-19 outbreaks in health and care settings, sentinel surveillance programmes in the community and acute hospitals and targeted sequencing based on public health risk assessment/clinical requests and virological changes e.g. new variant of concern. There is typically a lag time of 1-3 weeks between a COVID-19 case being notified, selected for sequencing and SARS-CoV-2 sequencing being completed. Therefore, the proportion of notified COVID-19 cases notified in this time period from whom specimens are ultimately sequenced will be higher than currently reported here. The HPSC link sequencing results received from laboratories to epidemiological data on COVID-19 cases reported on the CIDR system. This report summarises WGS results and epidemiological data for COVID-19 cases that have been sequenced in Ireland since week 40 2024 (specimen dates between 29/09/2024 and 15/11/2025). The SARS-CoV-2 sequencing results included in this report reflect all data available as of 29/12/2025.

National SARS-CoV-2 Wastewater Surveillance Programme: A detailed description of the process involved for wastewater collection, sampling and analyses is available in the routinely published [National SARS-CoV-2 Wastewater Surveillance Programme Report] (https://www.hpsc.ie/a-z/nationalwastewatersurveillanceprogramme/)


10 Appendix

Appendix Table 1: Number and incidence of notified laboratory-confirmed cases of COVID-19, influenza and RSV by age, sex and HSE Health Region, from week 40 2025, to week 4 2026. Data source: CIDR

Number of cases (incidence per 100,000 population)

All pathogens

COVID-19

Influenza

RSV

Cases

32,846 (637.9)

3,832 (74.4)

23,443 (455.3)

5,571 (108.2)

Age groups (years)

<1

2,017 (3,489.9)

256 (442.9)

806 (1,394.6)

955 (1,652.4)

1-4

5,160 (2,171.5)

264 (111.1)

2,895 (1,218.3)

2,001 (842.1)

5-14

3,432 (478.7)

239 (33.3)

2,911 (406.1)

282 (39.3)

15-44

6,685 (323.4)

630 (30.5)

5,615 (271.6)

440 (21.3)

45-64

3,938 (304.5)

580 (44.8)

2,904 (224.5)

454 (35.1)

65-79

5,952 (999.9)

909 (152.7)

4,346 (730.1)

697 (117.1)

>80

5,659 (3,126.1)

954 (527.0)

3,963 (2,189.2)

742 (409.9)

Median age (IQR)

40 (6-74)

63 (27-79)

41 (11-74)

3 (1-66)

Sex

Male

15,170 (596.2)

1,795 (70.5)

10,625 (417.6)

2,750 (108.1)

Female

17,642 (677.3)

2,036 (78.2)

12,795 (491.2)

2,811 (107.9)

HSE Health Regions

Dublin and North East

7,232 (609.2)

805 (67.8)

5433 (457.7)

994 (83.7)

Dublin and Midlands

6,008 (557.5)

664 (61.6)

4316 (400.5)

1028 (95.4)

Dublin and South East

7,362 (758.1)

925 (95.3)

5335 (549.4)

1102 (113.5)

South West

4,768 (643.8)

620 (83.7)

3226 (435.6)

922 (124.5)

Mid West

2,396 (580.1)

338 (81.8)

1634 (395.6)

424 (102.6)

West and North West

5,071 (667.5)

479 (63.1)

3494 (459.9)

1098 (144.5)


Appendix Table 2: Number and incidence of notified hospitalised laboratory-confirmed cases of COVID-19, influenza and RSV by age, sex and HSE Health Region from week 40 2025 to week 4 2026. Data source: CIDR

Number of cases (incidence per 100,000 population)

All pathogens

COVID-19

Influenza

RSV

Cases

8,668 (168.3)

1,382 (26.8)

5,429 (105.4)

1,857 (36.1)

Age groups (years)

<1

659 (1,140.2)

103 (178.2)

220 (380.6)

336 (581.4)

1-4

1,514 (637.2)

111 (46.7)

718 (302.2)

685 (288.3)

5-14

913 (127.4)

96 (13.4)

696 (97.1)

121 (16.9)

15-44

920 (44.5)

145 (7.0)

682 (33.0)

93 (4.5)

45-64

901 (69.7)

169 (13.1)

592 (45.8)

140 (10.8)

65-79

1,881 (316.0)

371 (62.3)

1,265 (212.5)

245 (41.2)

>80

1,879 (1,038.0)

387 (213.8)

1,255 (693.3)

237 (130.9)

Median age (IQR)

54 (4-78)

68 (26-81)

60 (9-79)

3 (1-66)

Sex

Male

4,189 (164.6)

710 (27.9)

2,527 (99.3)

952 (37.4)

Female

4,473 (171.7)

672 (25.8)

2,898 (111.3)

903 (34.7)

HSE Health Regions

Dublin and North East

972 (81.9)

201 (16.9)

612 (51.6)

159 (13.4)

Dublin and Midlands

1,410 (130.8)

268 (24.9)

871 (80.8)

271 (25.1)

Dublin and South East

2,060 (212.1)

280 (28.8)

1300 (133.9)

480 (49.4)

South West

1,165 (157.3)

217 (29.3)

683 (92.2)

265 (35.8)

Mid West

1,172 (283.7)

180 (43.6)

747 (180.8)

245 (59.3)

West and North West

1,882 (247.7)

235 (30.9)

1212 (159.5)

435 (57.3)


Appendix Table 3: Number and percentage of test positive Sentinel GP ARI specimens by respiratory virus for the most recent two weeks 4 2026, week 5 2026 and the 2025/2026 season to date. Data source: NVRL. Note: week number follows the ISO calendar

Week 4 2026 (N = 167)

Week 5 2026 (N = 67)

2025/2026 (N = 3362)

Virus

Total positive

% positive

Total positive

% positive

Total positive

% positive

SARS-CoV-2

3

1.8

3

4.5

105

3.1

Influenza Virus

22

13.2

11

16.4

1,041

31.0

Respiratory Syncytial Virus (RSV)

18

10.8

5

7.5

174

5.2

Rhino/enterovirus

17

10.2

5

7.5

491

14.6

Adenovirus

1

0.6

0

0.0

24

0.7

Bocavirus

1

0.6

0

0.0

10

0.3

Human metapneumovirus (hMPV)

11

6.6

8

11.9

122

3.6

Parainfluenza virus type 1 (PIV-1)

0

0.0

0

0.0

21

0.6

Parainfluenza virus type 2 (PIV-2)

0

0.0

0

0.0

1

0.0

Parainfluenza virus type 3 (PIV-3)

3

1.8

2

3.0

31

0.9

Parainfluenza virus type 4 (PIV-4)

1

0.6

1

1.5

48

1.4


Appendix Table 4: Number and percentage positive NVRL non-sentinel respiratory specimens by respiratory virus, week 4 2026, week 5 2026 and the 2025/2026 season to date. Data source: NVRL. Note: week number follows the ISO calendar

Week 4 2026 (N = 308)

Week 5 2026 (N = 32)

2025/2026 (N = 6404)

Virus

Total positive

% positive

Total positive

% positive

Total positive

% positive

SARS-CoV-2

3

1.0

2

6.2

134

2.1

Influenza Virus

35

11.4

3

9.4

1,674

26.1

Respiratory Syncytial Virus (RSV)

44

14.3

2

6.2

545

8.5

Rhino/enterovirus

24

7.8

2

6.2

693

10.8

Adenovirus

0

0.0

0

0.0

40

0.6

Bocavirus

1

0.3

0

0.0

26

0.4

Human metapneumovirus (hMPV)

16

5.2

0

0.0

138

2.2

Parainfluenza virus type 1 (PIV-1)

3

1.0

1

3.1

27

0.4

Parainfluenza virus type 2 (PIV-2)

0

0.0

0

0.0

2

0.0

Parainfluenza virus type 3 (PIV-3)

11

3.6

0

0.0

59

0.9

Parainfluenza virus type 4 (PIV-4)

1

0.3

0

0.0

42

0.7


Appendix Table 5: Influenza type and sub-type distribution among sentinel GP ARI and non-sentinel respiratory influenza positive specimens for the most recent two weeks 4 2026, week 5 2026 and the 2025/2026 season to date. Data source: NVRL. Note: week number follows the ISO calendar

Influenza A

Influenza B

Time period

Specimen source

Total influenza positive

Total

A(H1)pdm09

A(H3)

A(not subtyped)

Total

B Victoria

B (unspecified)

Week 4 2026

Sentinel GP ARI

22

21

7

14

0

1

0

1

Non-sentinel respiratory

35

35

18

17

0

0

0

0

Total

57

56

25

31

0

1

0

1

Week 5 2026

Sentinel GP ARI

11

11

1

10

0

0

0

0

Non-sentinel respiratory

3

3

1

2

0

0

0

0

Total

14

14

2

12

0

0

0

0

Season to date

Sentinel GP ARI

1,041

1,035

70

963

2

6

0

6

Non-sentinel respiratory

1,674

1,670

223

1,422

25

4

1

3

Total

2,715

2,705

293

2,385

27

10

1

9


Appendix Table 6: RSV type distribution among sentinel GP ARI and non-sentinel respiratory RSV positive specimens for the most recent two weeks 4 2026, week 5 2026 and the 2025/2026 season to date. Data source: NVRL. Note: week number follows the ISO calendar

Time period

Specimen source

Total RSV positive

RSV A

RSV B

RSV (unspecified)

Week 4 2026

Sentinel GP ARI

18

9

9

0

Non-sentinel respiratory

44

23

21

0

Total

62

32

30

0

Week 5 2026

Sentinel GP ARI

5

3

2

0

Non-sentinel respiratory

2

1

1

0

Total

7

4

3

0

Season to date

Sentinel GP ARI

174

75

99

0

Non-sentinel respiratory

545

309

236

0

Total

719

384

335

0