Feb 28, 2025 · WHO fact sheet on influenza: includes key facts, definition, symptoms, transmission, seasonal epidemics, effects, prevention, WHO response.

Mar 25, 2025 · Seasonal influenza is an acute respiratory infection caused by influenza viruses which circulate in all parts of the world. It is characterized by a sudden onset of fever, cough (usually dry), …

Nov 27, 2009 · Influenza is an acute viral infection that primarily attacks the upper respiratory tract, including the nose, throat, bronchi and, less frequently, the lungs. The disease occurs worldwide and …

Nov 30, 2025 · Seasonal influenza (‘the flu’) is an acute respiratory infection caused by influenza viruses that circulate globally and year-round. It can cause illness ranging from mild to severe, sometimes …

Feb 28, 2025 · 概述 季节性流感（流感）是由流感病毒引起的急性呼吸道感染。季节性流感在世界各地都很常见。大多数人不治而愈。 当人们咳嗽或打喷嚏时，流感很容易在人与人之间传播。接种疫苗是 …

Sep 26, 2025 · The World Health Organization (WHO) today announced its recommendations for the viral composition of influenza vaccines for use in the 2026 influenza season in the southern …

Influenza, or the flu, is both a seasonal and a pandemic virus. Every year, mainly during the winter season, seasonal influenza infects as many as 1 billion people. This makes it one of the most …

Nov 25, 2025 · Influenza season has started about 4 weeks earlier than usual in the WHO European Region. However, this is not out of the ordinary and current trends are similar to those observed in …

FluNet is a global web-based tool for influenza virological surveillance first launched in 1997.

Oct 31, 2017 · National Influenza Centres collect virus specimens in their country and perform preliminary analysis. They ship representative clinical specimens and isolated viruses to WHO CCs …