March 2, 2007

Nasal flu spray found to also help very young

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Kathryn Edwards, M.D.

Nasal flu spray found to also help very young

A new study co-authored by Vanderbilt's Kathryn Edwards, M.D., suggests that the nasal spray flu vaccine is twice as effective as the flu shot in children ages 6 months to 5 years.

The nasal spray flu vaccine, licensed for children over 5 years of age as Flumist, has been available for some time. It has not been available, however, for use in children under 5 years or in anyone with a history of asthma-like symptoms, which disappointed some parents of younger children who had been awaiting an option to the injection form of the flu shot.

“We suspected the live, weakened virus might offer younger children more protection and this study shows that it does,” said Edwards, professor of Pediatrics. “It works better in children because they have not been infected with the influenza vaccine many times before and they have not received vaccine many times before, so the live vaccine virus has a better “take,” or works better, in the young children than in the adults.”

Another compelling reason to expand the recommended age for use of the live vaccine is the possibility it may help to offset flu vaccine shortages that have happened almost annually for the last five years.

This study took place at 249 sites in 16 countries, involving 7,852 children who completed the trial. It directly compared the inactivated flu shot with the live attenuated nasal spray.

While 55 percent fewer children got the flu when taking the nasal spray, there were more side effects like wheezing (3.8 percent versus 2.1 percent), and hospitalizations were more frequent among the 6- to 11-month-old infants who received the nasal flu vaccine.

“The increase in wheezing in children less than 1 year of age who received their first dose of the live vaccine is of concern,” Edwards said. “For that reason the vaccine will not be licensed for children less than 1 year of age or for use in children with underlying asthma.”

Edwards' study, entitled “Live attenuated versus Inactivated Influenza Vaccine in Infants and Young Children” was published recently in the New England Journal of Medicine.

According to Edwards, it is welcome news because the success of the nasal spray in this large study could lead to approval for younger children, perhaps as soon as the next flu season.