Severe acute respiratory infections (SARI) surveillance report, Ireland
Weekly Report on Severe Acute Respiratory Infections (SARI), Ireland
Week 4 2026 (week ending 25/01/2026)
Report prepared on 29/01/2026
1 About this report
SARI surveillance uses the ISO week date system, in which each week runs from Monday to Sunday. This differs from the week definition used in the national infectious disease notification system in Ireland, where weeks run from Sunday to Saturday. Because of this difference, the ISO week calendar (SARI) did not include a Week 53 in 2025, whereas the notification system did. For details of ISO weeks in 2026, see ISO Weeks Calendar.
Since week 40 2025, four sentinel hospital sites are participating in Ireland’s severe acute respiratory infections (SARI) surveillance programme. The most recent addition is Children’s Health Ireland at Crumlin (CHI-C), commencing on 29th September 2025. St Vincent’s University Hospital (SVUH) was the first site to join, commencing SARI surveillance on 5th July 2021. This was followed by St James’s Hospital (SJH) and University Hospital Limerick (UHL, paediatric cases only) both commenced on 30th September 2024 (Week 40 2024).
The data presented in this report were extracted from the HPSC SARI surveillance database on 29/01/2026. These figures are provisional and subject to ongoing review, validation and updates. Consequently, they may differ from previously published data as refinements are made to improve accuracy.
Three of the four SARI sentinel hospital sites (75%) reported data for the current ISO week (W4 2026). Variations in the number of sentinel sites reporting each week, should be considered when comparing incidence rates and case numbers from previous weeks.
2 Key message
In ISO week 4 2026, SARI activity remained at moderate levels in Ireland; 79 SARI cases were reported from three of four sentinel hospital sites.
In week 4, RSV test positivity increased to 35% and was 45% in cases aged ≥15 years, influenza test positivity decreased to 10% and SARS-CoV-2 test positivity remained stable at 1%.
3 Summary
Note: Data presented below relate to ISO week
SARI case numbers and incidence:
79 SARI cases were admitted to three of the four SARI sentinel sites in week 4 2026.
SARI cases <15 years: 56 cases from two sentinel sites in week 4 2026.
SARI cases ≥15 years: 23 cases from one sentinel site in week 4 2026.
The incidence rates per 1,000 hospital admissions* were as follows:
All SARI cases: 131.0 in week 4 2026, compared to 152.4 in week 3 2026.
SARI cases <15 years: 240.3 in week 4 2026, compared to 285.7 in week 3 2026.
SARI cases ≥15 years: 62.2 in week 4 2026, compared to 117.4 in week 3.
*See technical notes section for further information on SARI hospital admissions data
Age profile (week 4 2026): 19% (n=15) cases were aged ≥65 years and 57% (n=45) cases aged <5 years:
All SARI cases: median age 4 years; IQR: 1-59 years.
SARI cases <15 years: median age 2 years, IQR: 1-4 years.
SARI cases ≥15 years: median age 75 years, IQR: 63-86 years.
Virus test positivity among SARI cases (week 4 2026): Among those tested (98.7%, n=78):
1.3% (n=1) tested positive for SARS-CoV-2, compared to 0.8% (n=1) in week 3 2026.
10.3% (n=8) tested positive for influenza A, compared to 21.5% (n=26) in week 3 2026. Among SARI cases aged <15 years and ≥15 years, 8.9% (n=5) and 13.6% (n=3) tested positive for influenza in week 4 2026, respectively.
34.6% (n=27) tested positive for RSV, compared to 24.8% (n=30) in week 3 2026. Among SARI cases aged <15 years and ≥15 years, 30.4% (n=17) and 45.5% (n=10) tested positive for RSV in week 4 2026, respectively.
Genomic surveillance (week 40 2025 to week 4 2026): Among SARI SARS-CoV-2 positive specimens sequenced (n=19), XFG was the dominant variant at 68.4% (n=13), followed by NB.1.8.1, at 21.1% (n=4). Variant BA.3.2 was identified in 5.3% (n=1) of specimens sequenced.
Influenza typing/subtyping (week 40 2025 to week 4 2026): For cases admitted since week 40 2025, influenza A was the predominant virus circulating amongst influenza positive SARI cases, consisting of A(H3) at 92.2% (n=272), followed by A(H1)pdm09 at 7.1% (n=21) among those subtyped. Currently, 184 are awaiting subtyping.
RSV typing/subtyping (week 40 2025 to week 4 2026): For cases admitted since week 40 2025, RSV A was co-circulating with RSV B, at 54.6% (n=71) and 45.5% (n=59) respectively, among those typed. Currently 43.5% (n=100) awaiting subtyping.
Underlying medical conditions (week 4 2026): Overall 49.4% (n=39) of SARI cases reported at least one underlying medical condition. This included 32.1% (n=18) of cases among those aged <15 years and 91.3% (n=21) among those aged ≥15 years.
Severe outcomes (week 40 2025 to week 4 2026):
4.9% (n=74) of SARI cases were admitted to ICU, this included 5.8% (n=48) among those aged <15 years and 3.8% (n=26) among those aged ≥15 years of age. Overall, the median length of stay was 1 days, IQR 1-4 days. Among the SARI cases admitted to ICU, 4.1% (n=3) were positive for SARS-CoV-2, 12.2% (n=9) for influenza and 16.2% (n=12) for RSV.
2.0% (n=36) of SARI cases died in hospital. The median age was 80 years, IQR 70-86 years, 86.1% (n=31) were ≥65 years of age
Vaccination status (week 40 2025 to week 3 2026): These data are reported with a one-week time lag.
Amongst SARI cases positive for SARS-CoV-2 (n=46), 87.0% (n=40) had NOT received a COVID-19 vaccine dose in the six months prior to the reported episode of illness.
Amongst SARI cases positive for influenza (n=408), 65.0% (n=265) had NOT received the 2025/2026 influenza season vaccine prior to the reported episode of illness.
4 SARI case numbers and incidence rates
4.1 SARI cases by site
Figure 4.1: Number of SARI cases by sentinel hospital site and by week of admission week 40 2024 to week 4 2026
Note: CHI-C included from week 40 2025, while only three hospital sites (SVUH, SJH & UHL) participated during the 2024/2025 season.
4.2 Incidence admissions
Figure 4.2: SARI age-specific incidence rates per 1,000 hospital admissions by week of admission week 40 2024 to week 4 2026
*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: CHI-C included from week 40 2025, while only three hospital sites (SVUH, SJH & UHL) participated during the 2024/2025 season.
4.3 SARI cases by age group
Figure 4.3: Number of SARI cases by age group and week of admission week 40 2024 to week 4 2026
Note: CHI-C included from week 40 2025, while only three hospital sites (SVUH, SJH & UHL) participated during the 2024/2025 season.
4.4 Incidence (seasons)
Figure 4.4: SARI incidence rates per 1,000 hospital admissions by week of admission between week 40 2024 and week 4 2026
Note: In the 2024/2025 season three hospital sites (SVUH, SJH & UHL) participated, and four sites (SVUH, SJH, UHL & CHI-C) participated in season 2025/2026.
5 Demographics
Table 1: Number and proportion of SARI cases by sex and age, for the current week (week 4 2026), last four weeks (week 1 2026 to week 4 2026) and current season (week 40 2025 to week 4 2026)
Current week | Last four weeks | Season total | ||
|---|---|---|---|---|
| W4 2026 | W1 2026-W4 2026 | W40 2025-W4 2026 | |
Characteristic | Category | N = 79 | N = 414 | N = 1,801 |
Gender | Female | 44 (55.7) | 204 (49.3) | 883 (49.0) |
Male | 35 (44.3) | 210 (50.7) | 918 (51.0) | |
Age <15 years (in years) | Median (IQR) | 2 (1 - 4) | 1 (0 - 3) | 1 (0 - 4) |
Range | 0 - 11 | 0 - 14 | 0 - 14 | |
Age ≥15 years (in years) | Median (IQR) | 75 (63 - 86) | 74 (64 - 84) | 74 (62 - 83) |
Range | 47 - 94 | 19 - 98 | 16 - 100 | |
Age groups (years) | <1 | 13 (16.5) | 54 (13.0) | 233 (12.9) |
1-4 | 32 (40.5) | 78 (18.8) | 399 (22.2) | |
5-14 | 11 (13.9) | 22 (5.3) | 196 (10.9) | |
15-34 | 0 (0.0) | 7 (1.7) | 49 (2.7) | |
35-64 | 8 (10.1) | 63 (15.2) | 234 (13.0) | |
65-79 | 6 (7.6) | 94 (22.7) | 361 (20.0) | |
80+ | 9 (11.4) | 96 (23.2) | 329 (18.3) | |
Patient residence | Residential care facility | 4 (5.1) | 44 (10.6) | 157 (8.7) |
Private residence/home | 74 (93.7) | 364 (87.9) | 1,626 (90.3) | |
Other/unknown residence | 1 (1.3) | 6 (1.4) | 18 (1.0) | |
Note: For the current week (week 4 2026), among the SARI cases aged ≥65 years, 20.0% (n=3) were resident in a residential care facility.
6 PCR testing for SARS-CoV-2, Influenza and RSV
SARI cases are tested on-site in each hospital by PCR for SARS-CoV-2, influenza and RSV on admission.
Table 2: Number and proportion of SARI cases PCR positive for SARS-CoV-2, influenza, and RSV for the current week, last four weeks (week 1 2026 to week 4 2026) and current season (week 40 2025 to week 4 2026)
| Current week | Last four weeks | Season total | ||||||
|---|---|---|---|---|---|---|---|---|---|
| W4 2026 | W1 2026-W4 2026 | W40 2025-W4 2026 | ||||||
| Overall | <15y | ≥15y | Overall | <15y | ≥15y | Overall | <15y | ≥15y |
SARS-CoV-2 | 1 (1.3) | 1 (1.8) | 0 (0.0) | 7 (1.7) | 2 (1.3) | 5 (1.9) | 61 (3.4) | 31 (3.8) | 30 (3.1) |
Influenza | 8 (10.3) | 5 (8.9) | 3 (13.6) | 83 (20.2) | 17 (11.1) | 66 (25.6) | 480 (27.0) | 196 (24.2) | 284 (29.4) |
RSV | 27 (34.6) | 17 (30.4) | 10 (45.5) | 87 (21.2) | 48 (31.6) | 39 (15.1) | 230 (13.0) | 167 (20.7) | 63 (6.5) |
1n (%) | |||||||||
Note: Between week 40 2025 to week 4 2026, 21 SARI cases were coinfected with more than one of the three viruses under surveillance.
A further breakdown of SARI test positivity by hospital site is available in the Appendix.
6.1 Number PCR positive
Figure 6.1: Number of SARI cases PCR positive for SARS-CoV-2, influenza and RSV by week of hospital admission week 40 2024 to week 4 2026
Note: CHI-C included from week 40 2025, while only three hospital sites (SVUH, SJH & UHL) participated during the 2024/2025 season.
6.2 Percentage PCR positive
Figure 6.2: Percentage of SARI cases PCR positive for SARS-CoV-2, influenza, RSV and overall positivity by week of hospital admission week 40 2024 to week 4 2026
Note: CHI-C included from week 40 2025, while only three hospital sites (SVUH, SJH & UHL) participated during the 2024/2025 season.
6.3 Percentage PCR positive by age group
Figure 6.3: Weekly positivity rate of SARI cases PCR positive for SARS-CoV-2, influenza and RSV by age group and by week of hospital admission week 40 2024 to week 4 2026
Note: CHI-C included from week 40 2025, while only three hospital sites (SVUH, SJH & UHL) participated during the 2024/2025 season. Y-axis scale may differ for each age group.
7 SARS-CoV-2 genomic analysis
Note: There is typically a lag time of at least 3 weeks between a case being admitted, positive samples selected for sequencing and sequencing being completed and reported.
For further information on circulating variants in Ireland, see Respiratory virus notification data hub - Health Protection Surveillance Centre (hpsc.ie) and Integrated Respiratory Virus Bulletin.
Table 3: Number and proportion of SARS CoV-2 positive SARI cases sequenced and reported by Pango lineage and variant week 40 2025 to week 4 2026
Variant | n | % | Pango Lineage | n | % |
|---|---|---|---|---|---|
XFG | 13 | 68.4 | XFG | 1 | 5.3 |
XFG.14.6 | 1 | 5.3 | |||
XFG.21 | 1 | 5.3 | |||
XFG.26 | 1 | 5.3 | |||
XFG.3 | 2 | 10.5 | |||
XFG.3.4.1 | 1 | 5.3 | |||
XFG.3.4.2 | 1 | 5.3 | |||
XFG.3.4.3 | 1 | 5.3 | |||
XFG.5.1 | 2 | 10.5 | |||
XFG.5.2 | 1 | 5.3 | |||
XFG.6.3.1 | 1 | 5.3 | |||
NB.1.8.1 | 4 | 21.1 | NB.1.8.1 | 1 | 5.3 |
PQ.17 | 2 | 10.5 | |||
PQ.8.1 | 1 | 5.3 | |||
BA.2.86 | 1 | 5.3 | LF.7 | 1 | 5.3 |
BA.3.2 | 1 | 5.3 | RE.2.1 | 1 | 5.3 |
Total | 19 | 100.1 | - | 19 | 100.4 |
Note: CHI-C included from week 40 2025, while only three hospital sites (SVUH, SJH & UHL) participated during the 2024/2025 season.
7.1 SARS-CoV-2 variants by week
Figure 7.1: Number of SARS CoV-2 positive SARI cases, by variant and week of hospital admission, week 40 2024 to week 4 2026
*Includes sub-lineage JN.1, excludes lineage KP.3
**Sample either not suitable for sequencing, or result is pending
Note: CHI-C included from week 40 2025, while only three hospital sites (SVUH, SJH & UHL) participated during the 2024/2025 season.
7.2 SARS-CoV-2 variants season to date
Figure 7.2: Proportion of SARS CoV-2 positive SARI cases sequenced, week 40 2025 to week 4 2026
*Includes sub-lineage JN.1, excludes lineage KP.3
Note: CHI-C included from week 40 2025, while only three hospital sites (SVUH, SJH & UHL) participated during the 2024/2025 season.
8 Influenza typing/subtyping
8.1 Influenza typing/subtyping by week
Figure 8.1: Number of influenza positive SARI cases by type/subtype and by week of admission, week 40 2024 to week 4 2026
Note: CHI-C included from week 40 2025, while only three hospital sites (SVUH, SJH & UHL) participated during the 2024/2025 season.
8.2 Influenza typing/subtyping (all age groups)
Figure 8.2: Proportion of subtyped influenza positive SARI cases by subtype/lineage, week 40 2025 to week 4 2026 (n=480)
Note: Unsubtyped influenza A positive samples (n=184) and B (n=1) excluded from figure 8.2
8.3 Influenza typing/subtyping (<15 years and ≥15 years)
Figure 8.3: Proportion of subtyped influenza positive SARI cases by subtype/lineage among those aged <15 years (n=145) and ≥15 years (n=150) week 40 2025 to week 4 2026
Note: Unsubtyped influenza A positive samples (n=184) and B (n=1) excluded from figure 8.3
9 RSV typing
9.1 RSV typing by week
Figure 9.1: Number of RSV positive SARI cases by RSV type and by week of admission, week 40 2024 to week 4 2026
Note: CHI-C included from week 40 2025, while only three hospital sites (SVUH, SJH & UHL) participated during the 2024/2025 season.
9.2 RSV typing (all age groups)
Figure 9.2: Proportion of typed RSV positive SARI cases by type, week 40 2025 to week 4 2026 (n=131)
Note: Untyped RSV positive samples (n=99) excluded from figure 9.2
10 Symptoms
Table 4: Number and proportion of SARI cases’ clinical symptoms, either at or prior to hospital admission, for the last four weeks (week 1 2026 to week 4 2026), and current season (week 40 2025 to week 4 2026)
Last four weeks | Season total | |||
|---|---|---|---|---|
W1 2026-W4 2026 | W40 2025-W4 2026 | |||
Clinical symptoms | <15y | ≥15y | <15y | ≥15y |
Cough | 132 (85.7) | 234 (90.0) | 684 (82.6) | 872 (89.6) |
Fever | 112 (72.7) | 136 (52.3) | 631 (76.2) | 539 (55.4) |
Shortness of breath | 28 (18.2) | 222 (85.4) | 126 (15.2) | 824 (84.7) |
General deterioration | 67 (43.5) | 120 (46.2) | 404 (48.8) | 413 (42.4) |
Malaise | 73 (47.4) | 59 (22.7) | 511 (61.7) | 197 (20.2) |
Coryza | 96 (62.3) | 0 (0.0) | 486 (58.7) | 0 (0.0) |
Increased work of breathing | 87 (56.5) | 0 (0.0) | 422 (51.0) | 0 (0.0) |
Nausea/Vomiting | 57 (37.0) | 36 (13.8) | 289 (34.9) | 125 (12.8) |
Sore throat | 30 (19.5) | 22 (8.5) | 253 (30.6) | 82 (8.4) |
Diarrhoea | 22 (14.3) | 17 (6.5) | 124 (15.0) | 74 (7.6) |
Headache | 9 (5.8) | 16 (6.2) | 34 (4.1) | 70 (7.2) |
Muscular pain | 1 (0.6) | 21 (8.1) | 12 (1.4) | 89 (9.1) |
Acute confusion | 0 (0.0) | 27 (10.4) | 1 (0.1) | 87 (8.9) |
Apnoea | 3 (1.9) | 0 (0.0) | 11 (1.3) | 1 (0.1) |
Sepsis | 0 (0.0) | 1 (0.4) | 3 (0.4) | 5 (0.5) |
Ageusia/Dysgeusia/Anosmia | 0 (0.0) | 0 (0.0) | 0 (0.0) | 3 (0.3) |
11 Underlying medical conditions and risk factors
SARI cases may be reported with one or more underlying medical conditions. Weekly proportions can be based on small numbers and vary from week to week, caution is therefore advised when interpreting changes in weekly proportions (Table 5).
Table 5: Number and proportion of SARI cases with underlying medical conditions reported on hospital admission, for the last four weeks (week 1 2026 to week 4 2026) and current season (week 40 2025 to week 4 2026)
| Last four weeks | Season total | ||
|---|---|---|---|---|
| W1 2026-W4 2026 | W40 2025-W4 2026 | ||
Condition | <15y | ≥15y | <15y | ≥15y |
Number of underlying medical conditions | ||||
None | 112 (72.7) | 11 (4.2) | 567 (68.5) | 59 (6.1) |
One | 31 (20.1) | 48 (18.5) | 190 (22.9) | 171 (17.6) |
Two | 9 (5.8) | 75 (28.8) | 55 (6.6) | 255 (26.2) |
Three or more | 2 (1.3) | 126 (48.5) | 16 (1.9) | 488 (50.2) |
Conditions reported | ||||
Heart disease | 6 (3.9) | 91 (35.0) | 49 (5.9) | 372 (38.2) |
Lung disease | 4 (2.6) | 91 (35.0) | 22 (2.7) | 397 (40.8) |
Hypertension | 1 (0.6) | 108 (41.5) | 5 (0.6) | 375 (38.5) |
Cancer | 1 (0.6) | 68 (26.2) | 12 (1.4) | 255 (26.2) |
Neurological disease | 7 (4.5) | 54 (20.8) | 43 (5.2) | 186 (19.1) |
Rheumatological disease | 0 (0.0) | 51 (19.6) | 2 (0.2) | 212 (21.8) |
Asthma | 7 (4.5) | 45 (17.3) | 65 (7.9) | 148 (15.2) |
Diabetes | 0 (0.0) | 39 (15.0) | 1 (0.1) | 148 (15.2) |
Immunocompromised | 1 (0.6) | 34 (13.1) | 17 (2.1) | 130 (13.4) |
Kidney disease | 1 (0.6) | 23 (8.8) | 6 (0.7) | 85 (8.7) |
Dementia | 0 (0.0) | 16 (6.2) | 0 (0.0) | 74 (7.6) |
Liver disease | 0 (0.0) | 20 (7.7) | 1 (0.1) | 71 (7.3) |
Prematurity* | 15 (9.7) | 0 (0.0) | 62 (7.5) | 0 (0.0) |
Intellectual disability | 9 (5.8) | 4 (1.5) | 44 (5.3) | 11 (1.1) |
Obesity | 0 (0.0) | 14 (5.4) | 2 (0.2) | 45 (4.6) |
Down syndrome | 3 (1.9) | 2 (0.8) | 18 (2.2) | 5 (0.5) |
Cystic fibrosis | 0 (0.0) | 2 (0.8) | 0 (0.0) | 3 (0.3) |
Asplenia | 0 (0.0) | 0 (0.0) | 1 (0.1) | 1 (0.1) |
Long COVID | 0 (0.0) | 1 (0.4) | 0 (0.0) | 1 (0.1) |
Tuberculosis | 0 (0.0) | 1 (0.4) | 0 (0.0) | 1 (0.1) |
*Prematurity: birth before 37 weeks gestation, this applies to paediatric cases under 2 years of age only.
12 Clinical course
12.1 Complications
Information on the clinical course during hospitalisation is only available after patient discharge, and there may be a delay between discharge and data collection, due to the manual data collection methods required. Furthermore, data collection is ongoing for those not yet discharged from hospital.
SARI cases could be reported with one or more complications; among those for whom discharge information is available the most common complication reported was pneumonia (Table 6).
Table 6: Number and proportion of SARI cases and complications among discharged SARI cases, for the last four weeks (week 1 2026 to week 4 2026), and current season (week 40 2025 to week 4 2026)
| Last four weeks | Season total | ||
|---|---|---|---|---|
| W1 2026-W4 2026 | W40 2025-W4 2026 | ||
Complication | <15y | ≥15y | <15y | ≥15y |
No complications | 48 (47.1) | 11 (11.5) | 354 (59.1) | 108 (16.9) |
Pneumonia | 22 (21.6) | 75 (78.1) | 110 (18.4) | 458 (71.8) |
Bronchiolitis | 12 (11.8) | 0 (0.0) | 66 (11.0) | 0 (0.0) |
Heart failure | 0 (0.0) | 7 (7.3) | 0 (0.0) | 45 (7.1) |
Acute kidney injury | 0 (0.0) | 4 (4.2) | 0 (0.0) | 44 (6.9) |
ARDS | 2 (2.0) | 0 (0.0) | 30 (5.0) | 1 (0.2) |
Secondary bacterial infections | 1 (1.0) | 1 (1.0) | 3 (0.5) | 16 (2.5) |
Sepsis | 0 (0.0) | 2 (2.1) | 0 (0.0) | 18 (2.8) |
Acute viral myositis | 0 (0.0) | 0 (0.0) | 4 (0.7) | 0 (0.0) |
Multi organ failure | 0 (0.0) | 0 (0.0) | 0 (0.0) | 2 (0.3) |
Respiratory complications | 0 (0.0) | 0 (0.0) | 1 (0.2) | 0 (0.0) |
Other complications | 8 (7.8) | 13 (13.5) | 24 (4.0) | 122 (19.1) |
The following complications have been removed from the table, as there are no cases reporting these conditions in the above time-periods: Myocarditis, Encephalitis, PIMS*, Acute atrial fibrillation
*Paediatric inflammatory multisystem syndrome
12.2 Respiratory support
Among SARI cases who have been discharged, the highest level of respiratory support received during hospitalisation is described in Table 7.
Table 7: Number and proportion of SARI cases by highest level of respiratory support received, among discharged SARI cases, for the last four weeks (week 1 2026 to week 4 2026), and current season (week 40 2025 to week 4 2026)
Last four weeks | Season total | |||
|---|---|---|---|---|
| W1 2026-W4 2026 | W40 2025-W4 2026 | ||
Respiratory support | <15y | ≥15y | <15y | ≥15y |
No respiratory support given | 59 (58%) | 43 (47%) | 387 (65%) | 226 (36%) |
Low-flow oxygen therapy | 37 (36%) | 37 (40%) | 146 (24%) | 283 (45%) |
Non-invasive ventilation | 5 (4.9%) | 12 (13%) | 61 (10%) | 111 (18%) |
Invasive ventilation | 1 (1.0%) | 0 (0%) | 3 (0.5%) | 7 (1.1%) |
1n (%) | ||||
13 Severe outcomes
SARI cases are considered to have severe outcomes if they were admitted to ICU and/or died during their hospital stay.
Data presented in this section are based on SARI cases who have been discharged.
13.1 All age groups
Table 8: Number and proportion of SARI cases with severe outcomes, for the last four weeks (week 1 2026 to week 4 2026), and current season (week 40 2025 to week 4 2026)
Last four weeks | Season total | |
|---|---|---|
| W1 2026-W4 2026 | W40 2025-W4 2026 |
| N = 414 | N = 1,801 |
Hospital length of stay (day) | ||
Median (IQR) | 3 (2 - 5) | 3 (2 - 6) |
Range | 1 - 23 | 1 - 69 |
Admitted to ICU, n (%) | 13 (4.6%) | 74 (4.9%) |
ICU length of stay (day) | ||
Median (IQR) | 3 (1 - 5) | 1 (1 - 4) |
Range | 1 - 9 | 0 - 17 |
Died in hospital, n (%) | 4 (1.0%) | 36 (2.0%) |
Note: Paediatric cases from UHL may be reported as admitted to ICU, if transferred to an ICU in another paediatric hospital. However, these cases are excluded from the calculation of length of stay in ICU.
13.2 Aged <15 years
Table 9: Number and proportion of SARI cases aged <15 years with severe outcomes, for the last four weeks (week 1 2026 to week 4 2026), and current season (week 40 2025 to week 4 2026)
Last four weeks | Season total | |
|---|---|---|
| W1 2026-W4 2026 | W40 2025-W4 2026 |
| N = 154 | N = 828 |
Hospital length of stay (day) | ||
Median (IQR) | 2 (1 - 3) | 2 (1 - 3) |
Range | 1 - 14 | 1 - 69 |
Admitted to ICU, n (%) | 8 (5.2%) | 48 (5.8%) |
ICU length of stay (day) | ||
Median (IQR) | - | 1 (1 - 2) |
Range | - | 0 - 9 |
Note: Paediatric cases from UHL may be reported as admitted to ICU, if transferred to an ICU in another paediatric hospital. However, these cases are excluded from the calculation of length of stay in ICU.
13.3 Aged ≥15 years
Table 10: Number and proportion of SARI cases aged 15 years and older with severe outcomes, for the last four weeks (week 1 2026 to week 4 2026), and current season (week 40 2025 to week 4 2026)
Last four weeks | Season total | |
|---|---|---|
| W1 2026-W4 2026 | W40 2025-W4 2026 |
| N = 260 | N = 973 |
Hospital length of stay (day) | ||
Median (IQR) | 5 (3 - 8) | 6 (3 - 10) |
Range | 2 - 23 | 1 - 60 |
Admitted to ICU, n (%) | 5 (3.8%) | 26 (3.8%) |
ICU length of stay (day) | ||
Median (IQR) | - | 4 (3 - 9) |
Range | - | 1 - 17 |
13.4 Aged ≥65 years
Table 11: Number and proportion of SARI cases aged 65 years and older with severe outcomes, for the last four weeks (week 1 2026 to week 4 2026), and current season (week 40 2025 to week 4 2026)
Last four weeks | Season total | |
|---|---|---|
| W1 2026-W4 2026 | W40 2025-W4 2026 |
| N = 190 | N = 690 |
Hospital length of stay (day) | ||
Median (IQR) | 5 (3 - 8) | 6 (4 - 11) |
Range | 2 - 23 | 1 - 60 |
Admitted to ICU, n (%) | 4 (4.2%) | 15 (3.2%) |
ICU length of stay (day) | ||
Median (IQR) | - | 4 (3 - 7) |
Range | - | 1 - 17 |
14 Vaccination status
Vaccination data are available approximately one week after cases are notified to HPSC, therefore the vaccination status for the current week’s SARI cases have been excluded from the below analysis.
14.1 COVID-19 vaccination status
During week 40 2025 to week 3 2026 among SARI cases PCR positive for SARS-CoV-2 (n=46), 87.0% (n=40) had NOT received a vaccine dose in the six months prior to the reported episode of illness.
Table 12: Characteristics of SARI cases positive for SARS-CoV-2 during week 40 2025 to week 3 2026 by time since last COVID-19 vaccine dose
| W40 2025-W3 2026 | |||
|---|---|---|---|---|
Characteristic | Category | <180 days | ≥180 days | Not vaccinated |
Gender | Female | 2 (11.8%) | 9 (52.9%) | 6 (35.3%) |
Male | 4 (13.8%) | 13 (44.8%) | 12 (41.4%) | |
Age (years) | Median (IQR) | 79 (76 - 83) | 71 (62 - 80) | 2 (1 - 4) |
Range | 67 - 85 | 9 - 95 | 0 - 9 | |
Age groups (years) | <2 | 0 (0.0%) | 0 (0.0%) | 7 (100.0%) |
2-17 | 0 (0.0%) | 1 (8.3%) | 11 (91.7%) | |
18-59 | 0 (0.0%) | 4 (100.0%) | 0 (0.0%) | |
60-69 | 1 (16.7%) | 5 (83.3%) | 0 (0.0%) | |
70-79 | 2 (28.6%) | 5 (71.4%) | 0 (0.0%) | |
80+ | 3 (30.0%) | 7 (70.0%) | 0 (0.0%) | |
Underlying medical conditions | Yes | 6 (18.2%) | 19 (57.6%) | 8 (24.2%) |
No | 0 (0.0%) | 3 (23.1%) | 10 (76.9%) | |
Unknown | 0 (0.0%) | 0 (0.0%) | 0 (0.0%) | |
Patient residence | Residential care facility | 0 (0.0%) | 1 (100.0%) | 0 (0.0%) |
Private residence/home | 6 (13.3%) | 21 (46.7%) | 18 (40.0%) | |
Other/unknown residence | 0 (0.0%) | 0 (0.0%) | 0 (0.0%) | |
SARS-CoV-2 positive SARI cases excluded from analysis:
- aged <6 months, 11 (18.3%)
- unknown vaccination status, 1 (1.7%)
- vaccinated within 14 days of symptom onset, 3 (5.0%)
14.2 Influenza vaccination status
During week 40 2025 to week 3 2026 among SARI cases PCR positive for influenza (n=420), 64.5% (n=271) had NOT received the 2025/2026 influenza season vaccine prior to the reported episode of illness.
Table 13: Characteristics of SARI cases positive for influenza during week 40 2025 to week 3 2026 by vaccination status for the 2025/2026 influenza season vaccine
| W40 2025-W3 2026 | ||
|---|---|---|---|
Characteristic | Category | Vaccinated | Not vaccinated |
Gender | Female | 83 (36.9%) | 142 (63.1%) |
Male | 66 (33.8%) | 129 (66.2%) | |
Age (years) | Median (IQR) | 78 (68 - 87) | 13 (4 - 64) |
Range | 1 - 99 | 0 - 92 | |
Age groups (years) | <2 | 2 (5.0%) | 38 (95.0%) |
2-17 | 8 (6.7%) | 111 (93.3%) | |
18-59 | 10 (17.5%) | 47 (82.5%) | |
60-69 | 22 (51.2%) | 21 (48.8%) | |
70-79 | 40 (64.5%) | 22 (35.5%) | |
80+ | 67 (67.7%) | 32 (32.3%) | |
Underlying medical conditions | Yes | 144 (44.7%) | 178 (55.3%) |
No | 5 (5.1%) | 93 (94.9%) | |
Unknown | 0 (0.0%) | 0 (0.0%) | |
Patient residence | Residential care facility | 24 (66.7%) | 12 (33.3%) |
Private residence/home | 125 (32.8%) | 256 (67.2%) | |
Other/unknown residence | 0 (0.0%) | 3 (100.0%) | |
Influenza positive SARI cases excluded from analysis:
- aged <6 months, 30 (6.4%)
- unknown vaccination status, 9 (1.9%)
- vaccinated within 14 days of symptom onset, 13 (2.8%)
15 Links to other national respiratory virus reports
Respiratory viruses
COVID-19
16 Appendix
Table A1: Number of SARI cases, number tested and positivity by hospital site for the current week (week 4 2026), previous two weeks (week 3 2026 and week 2 2026), and week 40 2025 to week 4 2026
Cases | SARS CoV-2 tested | SARS CoV-2 positive | Influenza & RSV tested | Influenza positive | RSV positive | |
|---|---|---|---|---|---|---|
Site | n | n | n (%) | n | n (%) | n (%) |
W4 2026 | 79 | 78 | 1 (1.3) | 78 | 8 (10.3) | 27 (34.6) |
SVUH | 23 | 22 | 0 (0.0) | 22 | 3 (13.6) | 10 (45.5) |
SJH | - | - | - | - | - | - |
UHL | 23 | 23 | 1 (4.3) | 23 | 5 (21.7) | 5 (21.7) |
CHI-C | 33 | 33 | 0 (0.0) | 33 | 0 (0.0) | 12 (36.4) |
W3 2026 | 123 | 121 | 1 (0.8) | 121 | 26 (21.5) | 30 (24.8) |
SVUH | 32 | 31 | 0 (0.0) | 31 | 8 (25.8) | 2 (6.5) |
SJH | 43 | 43 | 0 (0.0) | 43 | 12 (27.9) | 10 (23.3) |
UHL | - | - | - | - | - | - |
CHI-C | 48 | 47 | 1 (2.1) | 47 | 6 (12.8) | 18 (38.3) |
W2 2026 | 95 | 95 | 3 (3.2) | 95 | 15 (15.8) | 13 (13.7) |
SVUH | 36 | 36 | 1 (2.8) | 36 | 5 (13.9) | 3 (8.3) |
SJH | 32 | 32 | 2 (6.3) | 32 | 8 (25.0) | 4 (12.5) |
UHL | - | - | - | - | - | - |
CHI-C | 27 | 27 | 0 (0.0) | 27 | 2 (7.4) | 6 (22.2) |
W40 2025-W4 2026 | 1801 | 1776 | 61 (3.4) | 1776 | 480 (27.0) | 230 (13.0) |
SVUH | 444 | 440 | 18 (4.1) | 440 | 127 (28.9) | 32 (7.3) |
SJH | 529 | 526 | 12 (2.3) | 526 | 157 (29.8) | 31 (5.9) |
UHL | 333 | 328 | 17 (5.2) | 328 | 93 (28.4) | 73 (22.3) |
CHI-C | 495 | 482 | 14 (2.9) | 482 | 103 (21.4) | 94 (19.5) |
17 Technical Notes
17.1 SARI Surveillance objectives
Severe acute respiratory infection (SARI) is of major relevance to public health worldwide. Surveillance of SARI is essential to monitor the (co-) circulation of respiratory pathogens and to assess disease severity. Data collected as part of SARI surveillance can provide important early warning information in the context of respiratory disease outbreaks and pandemics. SARI data can also be used as a platform to measure vaccine and antiviral effectiveness and impact. The objectives of SARI surveillance are:
To describe the number and incidence of SARI cases by aetiology, time, place and person
To describe and monitor trends, intensity of activity and severity of SARI infections
To identify groups at risk of severe disease
To detect unusual and unexpected events
To assess the SARI burden of disease in the participating hospital
To assess and monitor vaccine effectiveness
17.2 Sentinel hospital SARI surveillance sites
SARI surveillance has been implemented in four sentinel hospital sites in Ireland.
St.Vincent’s University Hospital (SVUH), tertiary care adult hospital commenced 5th of July 2021 (week 27 2021)
St James’s Hospital (SJH), tertiary care adult hospital commenced 30th September 2024 (week 40 2024)
University Hospital Limerick (UHL), tertiary care hospital (for SARI surveillance purposes reports on paediatric cases only) commenced 30th September 2024 (week 40 2024)
Children’s Health Ireland at Crumlin (CHI-C) provides quarternary and tertiary healthcare services for children nationally and secondary care for the local catchment area, commenced 29th September 2025 (week 40 2025)
SVUH and SJH report on SARI cases aged 15 years and older while UHL and CHI-C report on SARI cases aged under 15 years.
17.3 Case definition
SARI cases are identified from new admissions, based on clinical symptoms. Patients that develop SARI during their admission are not included.
Clinical SARI case:
The European Centre for Disease Prevention and Control (ECDC) clinical SARI case definition was used for SARI surveillance in Ireland since week 34 2021. The case definition was adapted in Ireland for infants aged <6 months to include increased work of breathing and apnoea as relevant symptoms. This revised definition was applied to cases admitted from week 40 2025.
SARI case definition: A person hospitalised for at least 24 hours with acute respiratory infection and symptom onset within 14 days prior to hospital admission, with at least one of the following symptoms:
cough
fever
shortness of breath
sudden onset of anosmia, ageusia or dysgeusia
increased work of breathing*
apnoea*
*for infants aged <6 months
A SARI case refers to an individual patient episode of care.
17.4 Denominator data
Weekly denominator data on all-cause hospital admissions are provided by the sentinel hospital sites. SVUH, SJH and UHL provide data on admissions via the emergency department only; CHI-C provide data on admissions via the emergency department and non-emergency department routes (e.g. transfer from other hospitals, direct admission to speciality wards), excluding day cases and elective admissions.
17.5 Laboratory testing
SARS-CoV-2, influenza, and RSV PCR testing is carried out on admission.
SARI samples that are positive for SARS-CoV-2 and have a cycle threshold (Ct) value <25 are referred for whole genome sequencing (WGS). The molecular laboratories in SVUH, SJH and UHL are spoke WGS testing sites as part of the national SARS-CoV-2 WGS surveillance programme, for further information please see Whole Genome Sequencing Programme - Health Protection Surveillance Centre (hpsc.ie). SARI WGS testing is performed on-site at SVUH, SJH, UHL and CHI-C.
Samples that are PCR positive for influenza are sent to the National Virus Reference Laboratory (NVRL) for influenza typing/subtyping/genetic and antigenic characterisation.
Samples that are PCR positive for RSV are sent to the National Virus Reference Laboratory (NVRL) for RSV typing.
17.6 Data collection and reporting
St Vincent’s University Hospital: Clinical data are collected and managed using REDCap electronic data capture tools hosted at University College Dublin. Laboratory data are extracted from APEX, the laboratory information management system (LIMS), using IBM Cognos software hosted at SVUH.
St. James’s Hospital: Clinical data are collected and managed on a specifically adapted electronic form within the patient’s electronic patient record (EPR). Laboratory data are extracted from Telepath LIMS.
University Hospital Limerick: Clinical data are collected manually on the hard copy of the UHL SARI Case Report Form (CRF) and then recorded in the electronic SARI questionnaire on ICNET. Details of laboratory results are obtained from ICNET and are also recorded in the electronic SARI questionnaire on ICNET.
Children’s Health Ireland at Crumlin: Clinical data are collected and managed using REDCap electronic data capture tools hosted by the Children’s Research Centre. Laboratory data are extracted from Winpath LIMS.
Case-based data are reported by SVUH, SJH, UHL & CHI-C to the HSE Health Protection Surveillance Centre (HPSC) on a weekly basis. Data are also reported by HPSC to ECDC via The European Surveillance System (TESSy) on weekly basis as part of the European SARI surveillance programme.
COVID-19 and influenza vaccination data are obtained from the National COVID-19 Vaccination Management System (COVAX) and linked to SARI cases by the HSE-Integrated Information Service (IIS), where data are available.
17.7 Reference dates
Respiratory virus seasons and dates
The respiratory virus surveillance season runs from week 40 (early October) to week 20 (end of May). During this time, seasonal respiratory viruses usually circulate at higher levels, compared to the summer period (weeks 21 to 39). The seasonal comparisons used in this report refer to the respiratory virus surveillance season.
04/10/2021 (Week 40 2021) – start of the 2021/2022 season
03/10/2022 (Week 40 2022) – start of the 2022/2023 season
02/10/2023 (Week 40 2023) – start of the 2023/2024 season
30/09/2024 (Week 40 2024) – start of the 2024/2025 season
29/09/2025 (Week 40 2025) – start of the 2025/2026 season
SARI surveillance
05/07/2021 (Week 27 2021) – commenced of SARI surveillance at first sentinel hospital site (SVUH)
30/09/2024 (Week 40 2024) – commenced SARI surveillance at the second and third sentinel hospital sites (SJH & UHL)
29/09/2025 (Week 40 2025) – commenced SARI surveillance at the fourth sentinel hospital site (CHI-C)
Vaccination campaign dates
27/09/2021 (Week 39 2021) – first COVID-19 booster vaccination campaign commenced
22/04/2022 (Week 16 2022) – second COVID-19 booster vaccination campaign commenced
03/10/2022 (Week 40 2022) – Autumn 2022 COVID-19 booster vaccination campaign commenced
28/04/2023 (Week 17 2023) – Spring 2023 COVID-19 booster vaccination campaign commenced
02/10/2023 (Week 40 2023) – Autumn 2023 COVID-19 booster vaccination campaign commenced
22/04/2024 (Week 17 2024) – Spring 2024 COVID-19 booster vaccination campaign commenced
30/09/2024 (Week 40 2024) – Autumn 2024 influenza & COVID-19 booster vaccination campaign commenced
03/04/2025 (Week 13 2025) – Spring 2025 COVID-19 booster vaccination campaign commenced
02/10/2025 (Week 40 2025) – Autumn 2025 influenza & COVID-19 booster vaccination campaign commenced
Winter respiratory virus seasons
04/10/2021 (Week 40 2021) – start of the 2021/2022 season
03/10/2022 (Week 40 2022) – start of the 2022/2023 season
02/10/2023 (Week 40 2023) – start of the 2023/2024 season
30/09/2024 (Week 40 2024) – start of the 2024/2025 season
29/09/2025 (Week 40 2025) – start of the 2025/2026 season
Week number refers to the week of hospital admission. Weeks are from Monday to Sunday, as per the international ISO week.
The international ISO week runs from Monday to Sunday and is used as per ECDC/WHO/International reporting protocol.
17.8 Vaccination status definitions
For the purposes of SARI surveillance, vaccination status of cases is as follows:
Vaccinated COVID case: A confirmed case of COVID-19 who received any dose of a COVID-19 vaccine, ≥14 days before onset of symptoms.
Unvaccinated COVID-19 case: A confirmed case of COVID-19 who did not receive any dose of a COVID-19 vaccine i.e. was never vaccinated.
Time since vaccination: For a vaccinated COVID-19 case, this is the time between the date of last dose vaccination and the date of symptom onset and categorised as <180 days or ≥180 days since vaccination.
Vaccinated influenza case: A confirmed case of influenza will be considered as vaccinated against influenza if they received one dose of the influenza vaccine as part of the current season’s influenza vaccination campaign ≥14 days before onset of symptoms.
Unvaccinated influenza case: A confirmed case of influenza will be considered as unvaccinated if they did not receive an influenza vaccine as part of the current season’s influenza vaccination campaign or if they were vaccinated after onset of symptoms.
Vaccine status unknown: The SARI patient is reported on the SARI hospital clinical questionnaire as vaccinated, however there is no identifiable linked record of COVID-19 vaccination and/or influenza vaccination on the National Immunisation system (COVAX). Vaccination status is reported as unknown, until verified on the National Immunisation system.
18 Acknowledgements
Sincere thanks are extended to all those who participate in SARI surveillance, including those in St. Vincent’s University Hospital, St James’s Hospital, University Hospital Limerick, Children’s Health Ireland at Crumlin and the National Virus Reference Laboratory. Thanks to members of the HSE Integrated Information Services (IIS) for work on the SARI-COVAX data linkages.
This report was produced by the SARI surveillance team at HPSC, using R studio software.