On Sept. 20, 2007, the U.S. Food and Drug Administration (FDA) approved use of FluMist nasal-spray influenza vaccine in children age 2-4 years makes a needle-free influenza vaccine available for small children in the U.S. for the first time.

The FDA announced its approval of the nasal-spray vaccine, which contains a weakened form of live virus, yesterday. The vaccine, made by MedImmune, Gaithersburg, Md., was previously approved only for healthy people between the ages of 5 and 49.

MedImmune had asked the FDA to approve the vaccine for children aged 1 through 4 years with no history of wheezing, according to previous reports. But the FDA withheld approval of FluMist for children younger than 2 years because clinical trials showed an increased risk of hospitalization and wheezing for that group. The agency also said the vaccine should not be given to children under age 5 who have recurrent wheezing because it may trigger increased wheezing.

The FDA said its action means three flu vaccines are available in the United States for children younger than 5 years. Fluzone, made by Sanofi Pasteur Inc., Swiftwater, Pa., is approved for anyone older than 6 months, and Fluvirin, made by Novartis Vaccines and Diagnostics, Liverpool, England, is licensed for ages 4 and up.

About 6,400 children aged 6 to 59 months received FluMist in three clinical trials of the vaccine’s safety and effectiveness, according to the FDA. Two studies compared FluMist with a placebo vaccine and showed it was effective in preventing flu.

The third study compared FluMist with a conventional flu shot containing inactivated virus, the FDA reported. There were 53 flu cases among 3,900 children who received FluMist, versus 93 cases among an equal number of children who received the conventional vaccine, the agency said.

Common side effects of the spray vaccine were generally mild and typically included a runny nose and/or nasal congestion, plus a slight fever, the FDA said.