It is characterized by a sudden onset of fever, cough. Influenza is an acute viral infection that primarily attacks the upper respiratory tract, including the nose, throat, bronchi and, less frequently, the lungs. Influenza (flu) is a contagious respiratory illness caused by influenza viruses.
It is characterized by a sudden onset of fever, cough (usually dry),. It can cause illness ranging from mild to severe,. This makes it one of the most.
It can cause mild to severe illness. Who fact sheet on influenza: Every year, mainly during the winter season, seasonal influenza infects as many as 1 billion people. Influenza, or the flu, is both a seasonal and a pandemic virus.
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. Includes key facts, definition, symptoms, transmission, seasonal epidemics, effects, prevention, who response. Seasonal influenza is an acute respiratory infection caused by influenza viruses which circulate in all parts of the world. Seasonal influenza is an acute respiratory infection caused by influenza viruses which circulate in all parts of the world.