The nasal spray to which you're referring, known by the trade name FluMist, was originally approved in 2003 by the U.S. Food and Drug Administration for children over five and adults under 50. It is a vaccine administered by a single spritz in each nostril. The spray was designed for people who are vulnerable to flu but don't like having shots. It has minimal side effects - runny nose, scratchy throat, or mild cold symptoms that last a day or so.
In September, 2007, the FDA approved the use of FluMist in children ages two to five after three studies including some 6,400 youngsters aged six months to almost five years showed that it is safe and effective for this age group. Two of the three studies compared FluMist to a placebo spray containing no vaccine. FluMist worked much better than the placebo for flu prevention. The third trial compared FluMist to flu shots - both were effective, though neither worked 100 percent of the time. As approved, the FluMist dosage for kids between the ages of two and eight (who haven't already had flu shots) is two spritzes in each nostril, administered at least one month apart. FluMist isn't recommended for children under two because of an increased risk of wheezing and hospitalization.
FluMist is a live, attenuated (weakened) virus as opposed to the inactivated virus given in flu shots. For this reason, it isn't suitable for older people at risk of pneumonia, pregnant women, and people with weakened immune systems such as AIDS and cancer patients. Nor is it safe for anyone sensitive to eggs (a component of the vaccine), children or teenagers on aspirin therapy, those with asthma, immune deficiencies or anyone with Guillain-Barré syndrome (a neurological disorder that developed among hundreds of people immunized in 1976 against "swine flu").
I recommend flu shots for those over 65, as well as anyone with a weakened immune or respiratory system, nursing home residents, and health care workers who have regular contact with patients. Pregnant women whose last two trimesters fall during flu season (generally November to April) might consider getting the shot. The U.S. Centers for Disease Control currently recommends annual flu shots for all children from the age of six months to nearly five years.
Andrew Weil, M.D.