The U.S. government has approved a nasal spray vaccine that offers the first alternative to flu shots.

The Food and Drug Administration says the vaccine mist, called FluMist, can be used by healthy people between the ages of five and 49 - a population of about 160 million Americans that typically avoids flu shots.

The drug's manufacturer (MedImmune) says the vaccine will be available to the public ahead of the upcoming flu season, which starts in November.

Officials say the new drug is not suitable for children under five and patients over 50. The spray is also not recommended for people with asthma or other respiratory diseases. The Centers for Disease Control advises people in both categories to seek flu shots.

Authorities say they expect the inhaled vaccine to prevent some of the more than 100,000 flu-related hospitalizations that occur annually in the United States. About 36,000 Americans die each year from influenza.