Permanent complications are rare, but influenza can be fatal for some people. Usually one to five days after exposure. Influenza is highly contagious and is transmitted through droplets from the nose and throat of an infected person who coughs or sneezes. Washing hands may help prevent illness because flu can be transmitted by direct hand to hand contact or by touching an object after an infected person has touched it with contaminated hands. The contagious period varies, but normally begins the day before symptoms appear and lasts for a week.
Flu occurs most often in the winter.
Flu-like symptoms in summer months are usually due to other viruses. Anyone can get influenza. In a flu epidemic year, up to 50 percent of the non-immunized population will contract influenza. Flu season begins in November in Washington, so shots should be given in late October. People who get a flu shot too early can be at risk again later in the season because the shot only lasts about six months.