Influenza virus is one of the most ubiquitous organisms on the planet, causing illness in much of the population each year. The dynamic nature of the influenza virus requires similarly dynamic surveillance and prevention initiatives. The efforts of national surveillance programs, overseen by the World Health Organization and administered by institutions such as the U.S. Centers for Disease Control and Prevention, the U.S. armed forces, and 60 to 70 collaborating laboratories, annually culminate in the development of effective influenza vaccines. The U.S. Air Force's contribution is via Project Gargle, through which bases in various locations worldwide conduct active surveillance and submit throat swab specimens for virus isolation and characterization; the results of these laboratory analyses help determine the composition of the following year's influenza vaccine. These collaborative efforts have resulted in an identical or close antigenic match between vaccine and epidemic strains in 8 of the last 9 influenza seasons.