Flu season in Sweden
Current flu activity in Sweden, based on ECDC ERVISS weekly data, set against the parallel COVID-19 and RSV trajectories.
Influenza: Low
Low
The source currently reports no meaningful activity (as of 16 Aug 2026).
Data window: Week 33 · Aug 10 – Aug 16 · Source: ECDC (weekly) · Source on seasonal break, next data from week 40
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View the last 8 weeks
In week 33 of 2026, Influenza activity in Sweden is classified as low.
The source reports no meaningful activity across these weeks; a week-over-week percentage would be pure noise here.
The last 8 reported weeks
| Week | Relative | Level | vs prior week |
|---|---|---|---|
| Week 33 | – | Low | – |
| Week 32 | – | Low | – |
| Week 31 | – | Low | – |
| Week 30 | – | Low | – |
| Week 29 | – | Low | – |
| Week 28 | – | Low | – |
| Week 27 | – | Low | – |
| Week 26 | – | Low | – |
Across these weeks the source reports no meaningful activity, the values sit at the floor of its scale.
Current activity
- InfluenzaLowstableWeek 33Trend: stable · Week 33
- COVID-19LowstableWeek 33Trend: stable · Week 33
- RSVLowstableWeek 33Trend: stable · Week 33
What this means
In week 33 of 2026, activity of influenza (seasonal flu) in Sweden is low. The trend, derived from clinical surveillance, is stable. Activity has barely shifted over the past few weeks.
Data, context and methodology
The current picture for Sweden is built on the European Respiratory Virus Surveillance Summary (ERVISS), published weekly by the European Centre for Disease Prevention and Control (ECDC). Folkhälsomyndigheten is the national public-health authority that feeds ERVISS with sentinel primary care and virology data. Sweden does not always report ILI consultation rates to ERVISS; when national ILI is missing we fall back to the EU median so the signal remains comparable.
ECDC ERVISS
ERVISS is ECDC's weekly pan-European surveillance summary for influenza, SARS-CoV-2 and RSV. National authorities, in Sweden's case Folkhälsomyndigheten, submit harmonised indicators every week, which ECDC publishes in a standardised dataset on Thursdays. Using ERVISS rather than each country's native portal ensures cross-country comparability.
ILI / ARI consultation rates and positivity
Folkhälsomyndigheten operates a sentinel network of general practices that report weekly rates of patients consulting for influenza-like illness (ILI) or acute respiratory infection (ARI). A subset of patients is swabbed and tested by reference laboratories, producing pathogen-specific positivity rates for flu, SARS-CoV-2 and RSV.
Why this source
Combining consultation incidence with virological positivity yields a pathogen-specific weekly incidence signal (ILI × positivity / 100). This is the standard European methodology and provides a more robust view than either indicator alone: consultation rates capture illness burden, positivity confirms which pathogen is driving it.
Qualitative classification
The “low”, “moderate” and “high” categories follow seasonal reference values and epidemiological thresholds calibrated to match our classifications for other countries. The ILI × positivity / 100 product is scaled to comparable thresholds using a divisor of 3, which aligns European sentinel peaks with the consultation-equivalent scale used elsewhere. Data refreshes weekly when ECDC publishes the latest ERVISS update, typically on Thursdays.
Source and seasonal pattern by pathogen
- Influenza
- The classification is based on the ECDC ERVISS weekly reports, drawing on sentinel and virological data from the Public Health Agency of Sweden (Folkhälsomyndigheten); where national indicators are stale, the EU median is used as a fallback. Seasonally, infection waves in Sweden typically peak between January and March; activity is usually markedly lower during the summer months.
- COVID-19
- The classification is based on the ECDC ERVISS weekly reports, drawing on COVID-19 indicators from the Public Health Agency of Sweden (Folkhälsomyndigheten); where national indicators are stale, the EU median is used as a fallback. Seasonally, infection waves in Sweden typically peak during winter, with occasional summer waves driven by new variants; activity is usually markedly lower in late spring between waves.
- RSV
- The classification is based on the ECDC ERVISS weekly reports, drawing on RSV indicators from the Public Health Agency of Sweden (Folkhälsomyndigheten); where national indicators are stale, the EU median is used as a fallback. Seasonally, infection waves in Sweden typically peak between December and February; activity is usually markedly lower in spring and summer.
Frequently asked questions
When is flu season in Sweden?
Swedish flu seasons typically build through December and peak between January and March, somewhat later than central European peaks. The precise window shifts each year with the dominant influenza subtype and population immunity. Folkhälsomyndigheten's weekly reports describe the season in terms of rising, peak, declining, and low-activity phases rather than precise onset dates.
Who runs flu surveillance in Sweden?
Sweden's Public Health Agency, Folkhälsomyndigheten, runs national influenza surveillance. It combines mandatory reporting of laboratory-confirmed cases, the Webbsök web-search signal, sentinel physician reports, and the Svebar laboratory network. Weekly summaries are published openly and also reported to ECDC for inclusion in the European ERVISS platform.
How does Sweden report into European flu data?
Folkhälsomyndigheten transmits Sweden's weekly influenza, SARS-CoV-2, and RSV indicators to ECDC, where they appear in ERVISS, the European Respiratory Virus Surveillance Summary. This places Sweden's trajectory next to other Nordic countries (Norway, Finland, Denmark) and the rest of the EU/EEA using harmonised tiering. That harmonisation is what makes cross-border comparisons meaningful.
How does Sweden's flu season compare to Germany's?
Swedish peaks are generally a few weeks later than German peaks, and the whole winter curve sits slightly shifted toward February and March. This reflects Sweden's latitude and indoor-contact patterns. Because both countries report into ERVISS with the same methodology, the relative timing and intensity of their peaks are directly comparable in ECDC's published dashboards.
How does Folkhälsomyndigheten classify flu intensity?
Folkhälsomyndigheten classifies activity qualitatively (low, medium, high, very high) using established reference thresholds. These reflect historical ranges of consultation rates, positivity, and, where available, hospitalisation signals. The purpose is to describe whether the week's load is normal, elevated, or exceptional for the season, not to imply a precise incidence figure.
More situation reports
Data last refreshed: Sep 1, 2026, 10:25. Update cadence: weekly.
This page is not medical advice and does not replace consultation with a healthcare professional. For specific symptoms, please contact a medical professional.
About this page
Published by Renderei Martin GmbH, Berlin. No commercial interest in individual health recommendations. The app is optionally monetised via a freemium subscription.
Content is based exclusively on the linked official surveillance publications. Medical statements are curated against the guidance of RKI, ECDC and WHO.
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