Loading data…Virological surveillance of influenza and respiratory viruses in the Czech Republic — seasonal overviews 2012–2026, NIPH/NRL data.
Seasonal influenza overview
Laboratory-confirmed influenza A and B cases across the seasons 2012/13–2025/26. The drop in the 2020/21 and 2021/22 seasons reflects the effect of COVID-19 countermeasures (masks, contact restrictions). The running season is updated continuously, so its column keeps growing during the winter.
Influenza A vs. B — totals per season
Loading…Absolute counts of laboratory-confirmed detections per season, whole country. These are tested samples, not an estimate of total illness in the population.
Weekly course of the running season
Laboratory detections by calendar week, from the NRL’s weekly PDF reports — updated every week, including over the summer.
Weekly detections — season 2025/26
Loading…Absolute counts of laboratory detections per calendar week, whole country. Influenza A includes the H1N1pdm and H3N2 subtypes.
Positivity of laboratory specimens
Detection counts grow with the amount of testing — and testing keeps growing: about 16,000 specimens in the 2021/22 season, over 65,000 in 2024/25. Counts therefore cannot tell whether this season was stronger than the last one. Positivity — the share of positive specimens among those tested — cancels the testing volume out, so seasons can be compared.
Influenza positivity by week of the season
Loading…Share of specimens positive for influenza among those tested in the laboratory (non-sentinel system), in percent; each line is one season, the X axis runs from week 40 to week 20. Seasons from 2021/22 — before that, a few hundred hand-picked specimens were tested and the percentages are not comparable. Weeks with fewer than 30 specimens are not shown.
The weekly series shows the three main respiratory viruses side by side, each with its own number of specimens tested. Hover over a point to see how many specimens the percentage comes from.
Weekly positivity — influenza, RSV, SARS-CoV-2
Loading…Share of positive specimens among those tested, in percent, whole country, ECDC ERVISS data. The series starts in week 1/2025, since when ERVISS continuously reports the number of specimens tested for RSV. SARS-CoV-2 ends in week 33/2026: from the following week a different number of tested specimens is reported and the figures do not continue the series. The last 2–3 weeks are missing until the laboratories report their results.
The respiratory virological landscape
All monitored respiratory viruses (influenza, RSV, rhinoviruses, coronaviruses, adenoviruses…) across the seasons. The weekly course of the current season by region is on the Influenza — regional surveillance page.
Respiratory viruses — detections per season
Loading…Absolute counts of laboratory detections of each virus per season, whole country.
Note: series labels in the charts come from the Czech source data.
Surveillance background
The data come from the NRL for influenza and non-influenza respiratory viruses at the National Institute of Public Health (SZÚ) in Prague. Every epidemiological week the NRL publishes a report with virological test results from ARI/ILI patients; historical seasons are extracted from archived reports, the current season is downloaded automatically.
Monitored viruses:
- influenza A (H1N1pdm, H3N2) and influenza B
- RSV (respiratory syncytial virus)
- HRV (rhinoviruses), HAdV (adenoviruses), HPIV (parainfluenza viruses)
- HMPV (metapneumoviruses), CoV (seasonal coronaviruses), hBoV (bocaviruses)
- Mycoplasma pneumoniae (atypical pneumonia)
Further influenza resources
- SZÚ — current influenza/ARI reports
- WHO FluNet — Europe
- ECDC — seasonal influenza surveillance
- Influenza phylogeny (Nextstrain) — strain evolution and vaccine strain selection
Source: SZÚ Prague · NRL influenza · seasons 2012/13–2025/26 · category: laboratory detections (PCR/IF)