Influenza, also known as the flu, is a highly contagious respiratory disease caused by influenza viruses. Flu symptoms can range from mild to severe and include fever, cough, sore throat, body aches, fatigue, and sometimes vomiting and diarrhea.

When a person with flu talks, coughs or sneezes, the flu virus spreads through respiratory droplets. Influenza can also be transmitted by touching a surface infected with the virus and then touching the mouth or nose. Flu viruses are constantly changing, which is why a new flu vaccine is needed each year to protect against the most common strains.

While most people recover from the flu within a few days to two weeks, in some cases the flu can lead to serious complications such as pneumonia. Maintaining good hygiene habits such as frequent hand washing and covering the mouth and nose when coughing and sneezing is very important to prevent the spread of influenza.