Health News -- Influenza, commonly called the flu, is a highly contagious respiratory illness caused by a virus. Outbreaks of the flu virus begin as early as October and can last as late as the end of May, according to the Centers for Disease Control and Prevention (CDC). The single best way to protect against the flu is to get vaccinated each year. Each vaccine contains three influenza viruses; one A (H3N2) virus, one A (H1N1) virus, and one B virus. The viruses in the vaccine change each year based on data collected from around the globe throughout the year and scientists’ estimations about which types and strains will circulate in the upcoming season. About 2 weeks after vaccination, antibodies that provide protection against infection develop in the body, but that protection depends largely on the match between the virus strains in the vaccine and those in circulation. When predictions miss their mark, vaccines become largely ineffective, which was the case for the 2007-2008 flu season. But the days of using this “best guess” method may be numbered.
