The live, attenuated, cold-adapted influenza vaccine, also known as CAIV-T (FluMist) was safe and effective in children aged 60 months to 17 years in the second year of its use for prevention of flu.
The CAIV-T vaccine was first available for use during the 2003–2004 season and was designed to contain three flu strains that matched those recommended by the FDA for the annual trivalent inactivated vaccine. Robert B. Belshe, M.D., of St. Louis University and colleagues reviewed a safety trial that included 6,657 children aged 5–17 years and an efficacy trial including 312 children aged 60–71 months. (Clin. Infect. Dis. 2004;39;920–7).
The safety trial evaluated medically attended events within 42 days of vaccine administration. Overall, the frequency of events in four categories—acute respiratory events, acute gastrointestinal events, systemic bacterial infections, and rare events possibly associated with wild-type influenza—was not significantly different between the 4,452 children in the vaccine group and the 2,205 children in a placebo group.
Results from the efficacy study showed an efficacy rate of 87% for children aged 60 months and older and no significant increase in the frequency of fevers greater than 37.8° C. In addition, no significant increase in frequencies of runny nose, nasal congestion, vomiting, or muscle aches was noted among the vaccine recipients compared with the placebo group.
The data confirm that the efficacy of CAIV-T extends to the youngest children in the age range for which it is currently recommended, Peter F. Wright, M.D., of Vanderbilt University, Nashville, Tenn., said in an editorial (Clin. Infect. Dis. 2004;39:928–9).