Flu shots appear more effective than inhalants

The question: The flu vaccine, considered the best available protection against influenza, is available as a shot or a nasal spray. Does one delivery method offer better protection than the other?

This study randomly assigned 1,247 people, 18 to 46 years old, to receive a flu vaccine (either a flu shot or a nasal spray) or a placebo (again, either a shot or inhalant) before the start of the 2004-05 flu season. Flu shots (Fluzone) contained a killed virus; the nasal spray (FluMist) contained a live but weakened virus. If participants developed flu symptoms (cough or nasal congestion and fever, chills or body aches), laboratory analysis of throat swabs determined whether the illness was caused by an influenza virus. Flu shots were found to be successful at preventing the flu about 75 percent of the time; the nasal spray was deemed successful about 48 percent of the time.

Find this study in the Dec. 14 issue of the New England Journal of Medicine; abstract available at www.nejm.org.