Nasal spray vaccine 40 years in the making.

• Position: Influenza

The Food and Drug Administration's approval of a new nasal spray flu vaccine brings to fruition four decades of research by a University of Michigan, Ann Arbor, professor. FluMist, based on technology developed by Hunein "John" Maassab, emeritus professor of epidemiology at the School of Public Health, is available for use by healthy individuals between the ages of five and 49.

FluMist is a cold-adapted, live-attenuated, trivalent influenza virus inoculation. It is the only influenza vaccine delivered as a nasal mist to be commercially available in the U.S. It uses a live, but weakened, virus, administered to help develop immunity. This weakened virus is adapted to grow at the lower temperatures of the nasal passages, but not the warmer conditions of the lungs where influenza disease develops. A trivalent vaccine, like the flu shot, includes three different strains of vaccine. The Centers for Disease Control and Prevention, Atlanta, Ga., estimates that about 114,000 people in the U.S. each year are hospitalized, and about 20,000 die, because of flu.

Maassab began work on an influenza vaccine in the 1950s as a public health graduate student...