Flu season in Norway
Current flu, COVID-19 and RSV activity in Norway — based on ECDC ERVISS weekly data from the Norwegian Institute of Public Health (FHI). Rescaled into a consultation-equivalent signal for a qualitative low / moderate / high classification.
Current situation: Influenza
In week 15 of 2026, activity of influenza (seasonal flu) in Norway is low. The trend — derived from clinical surveillance — is stable. Over a four-week comparison, a clear decline is visible.
The classification is based on the ECDC ERVISS weekly reports, drawing on data from the Norwegian Institute of Public Health (FHI) via its sentinel GP network and wastewater surveillance. Seasonally, infection waves in Norway typically peak between January and March; activity is usually markedly lower during the summer months. How severe a given season becomes depends on the circulating virus variant and the population's immune status, among other factors.
Data sources and methodology
The current picture for Norway is built on the European Respiratory Virus Surveillance Summary (ERVISS), published weekly by the European Centre for Disease Prevention and Control (ECDC). the Norwegian Institute of Public Health (FHI) via its sentinel GP network and wastewater surveillance is the national public-health authority that feeds ERVISS with sentinel primary care and virology data.
ECDC ERVISS
ERVISS is ECDC's weekly pan-European surveillance summary for influenza, SARS-CoV-2 and RSV. National authorities — in Norway's case the Norwegian Institute of Public Health (FHI) via its sentinel GP network and wastewater surveillance — 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
the Norwegian Institute of Public Health (FHI) via its sentinel GP network and wastewater surveillance 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.
Frequently asked questions
When is flu season in Norway?
Norwegian flu activity usually starts rising in late December, peaks between January and March, and tails off by April. The exact onset and peak shift year to year with the dominant subtypes and residual immunity. FHI — the Norwegian Institute of Public Health (Folkehelseinstituttet) — publishes weekly influenza updates through its sentinel GP network and national reference laboratory. Nordic climates concentrate indoor contact in the darkest months, which shapes the winter respiratory curve.
How does FHI classify flu severity?
FHI describes influenza activity in qualitative bands — low, moderate, high, and very high — based on sentinel consultations, laboratory positivity, and hospital indicators. These classifications appear in the weekly respiratory-virus bulletin and are also reported to ECDC for the European Respiratory Virus Surveillance Summary (ERVISS). The qualitative framing helps clinicians and the public interpret whether the season is ordinary, elevated, or exceptional.
How is flu surveillance organised in Norway?
Norway's influenza surveillance combines a sentinel network of general practitioners, laboratory testing coordinated by FHI, hospital notifications of severe cases, and wastewater monitoring at selected treatment plants. Wastewater adds an early signal independent of test-seeking behaviour and complements the clinical indicators. Weekly bulletins summarise the full picture and feed ECDC ERVISS, which places Norway's trajectory alongside Sweden, Finland, and the rest of the EU/EEA.
Is the flu vaccine free in Norway?
Norway offers seasonal influenza vaccination at a reduced, subsidised cost for defined risk groups — older adults from 65 and up, pregnant women after the first trimester, people with chronic illnesses, and healthcare workers — delivered through GPs, pharmacies, and municipal services. Some municipalities and employer-paid schemes cover the full cost for certain groups. FHI reports vaccine-uptake estimates alongside the weekly surveillance bulletin.
How does Norway compare to its Nordic neighbours?
Because Norway reports into ECDC ERVISS with harmonised indicators, its weekly flu classification is directly comparable with Sweden, Denmark, Finland, and Iceland. Nordic countries typically see broadly similar peak windows between January and March. Lead–lag patterns of a few weeks are common and are visible in ECDC's side-by-side dashboards.
Want the actual numbers?
You'll find them in the app.
Here you only see the trend. In the app: exact incidence rates, “X out of 100 people infectious”, your personal risk based on age and pre-existing conditions, wastewater trends, 36 countries, home-screen widget.
