Flu season in China
Current flu activity in China — based on WHO FluNet + ILI% surveillance, set against the parallel COVID-19 and RSV trajectories.
Current situation: Influenza
In week 15 of 2026, activity of influenza (seasonal flu) in China is low. The trend — derived from clinical surveillance — is stable. A slight upward trend has emerged over recent weeks.
The classification is based on WHO FluNet combined with influenza-like illness (ILI%) indicators from the Chinese National Influenza Center; China reports separately for its northern and southern provinces, and the classification uses an ILI × positivity composite. Seasonally, infection waves in China typically peak between December and February in the north, with a more prolonged, bimodal pattern in the south; activity is usually markedly lower during the summer months in the north, while activity in the south fluctuates year-round. 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 China is built on WHO FluNet, supplemented by the Chinese National Influenza Center's weekly ILI percentage. The China National Influenza Center reports sentinel laboratory results to FluNet every week, and — uniquely among FluNet contributors — also publishes an ILI consultation percentage inside the dataset's comment field, which we use to produce an ECDC-style pathogen-specific signal when available.
WHO FluNet
FluNet is the WHO's weekly global influenza surveillance database. The China National Influenza Center submits the number of respiratory specimens tested and the number positive for influenza and, where available, RSV. This provides a consistent, internationally comparable baseline signal.
ILI percentage via LAB_RESULT_COMMENT
China embeds a weekly ILI consultation percentage inside FluNet's LAB_RESULT_COMMENT field. When this value is present we compute ILI × positivity / 100 — the same methodology used for ECDC ERVISS countries — which gives a pathogen-specific weekly incidence signal. When ILI% is missing we fall back to the FluNet positivity-rate method (positivity × scaling factor, 80 for flu and 50 for RSV).
Why this source
FluNet is the only weekly, internationally harmonised dataset for China, and the embedded ILI% lets us apply ECDC-style methodology where possible for improved comparability. COVID-19 is not available via FluNet and is therefore not shown.
Qualitative classification
The “low”, “moderate” and “high” categories follow seasonal reference values and epidemiological thresholds calibrated to match our classifications for other countries. Whether the ECDC-style ILI × positivity / 100 product or the FluNet positivity × scaling-factor signal is used, both are mapped to the same consultation-equivalent scale so results stay comparable across regions. Data refreshes weekly when WHO publishes the latest FluNet update.
Frequently asked questions
When is flu season in China?
China's flu pattern is bimodal and spatially split. Northern China follows a typical temperate pattern with peaks from December through February. Southern China shows a more prolonged season — often running from autumn through winter — and sometimes produces a secondary summer peak driven by subtropical conditions. The two regions are tracked and reported separately in national surveillance.
Who runs flu surveillance in China?
The China National Influenza Center (CNIC), hosted by the Chinese Center for Disease Control and Prevention (China CDC), coordinates influenza surveillance across roughly 550 sentinel hospitals and over 400 network laboratories. CNIC produces weekly influenza surveillance reports and transmits aggregated data to WHO FluNet, where China's northern and southern regions are represented as distinct signals.
How does China report into WHO FluNet?
CNIC transmits weekly sentinel indicators to WHO FluNet via the Western Pacific Regional Office. China is notable for reporting the north and south separately, which FluNet publishes as two distinct curves. China also uses FluNet's LAB_RESULT_COMMENT field to publish weekly ILI-percentage data for each region — an unusually detailed contribution within the FluNet schema.
Why are northern and southern China tracked separately?
Climate, latitude, and contact patterns differ sharply between northern and southern China, producing genuinely different influenza curves. The northern signal follows temperate seasonality with winter peaks. The southern signal is more complex, with prolonged activity and occasional summer peaks. Reporting them separately preserves signal clarity that would otherwise be lost in a single national average.
How is flu intensity classified in Chinese data?
CNIC classifies activity using ILI percentage against historical thresholds, reported separately for the north and south. Qualitative tiers — baseline, low, medium, high — are derived from those thresholds. Because the ILI% values are published through FluNet's LAB_RESULT_COMMENT field, the classification basis is unusually transparent compared with most FluNet contributors.
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.
