MedImmune’s Flu Vaccine Shows Efficacy

MedImmune’s data from a Phase III study showed that its next-generation investigational influenza vaccine, CAIV-T (cold adapted influenza vaccine, trivalent), was 55% more effective than the trivalent injectable inactivated influenza vaccine (TIV) in reducing influenza illness caused by any influenza strain in children six months to 59 months of age. The influenza attack rate was 8.6% for study participants receiving the flu shot compared to 3.9% for those who received CAIV-T (P <0.001). The data also showed that CAIV-T provided statistically significant improvements in reducing influenza illness caused by both matched and mismatched A strains as compared to the flu shot.

The study included 8,475 children at 249 sites in 16 countries in North America, Europe, the Middle East and Asia. Study participants were randomized one-to-one to receive either CAIV-T or the flu shot during the 2004-2005 flu season. Each participant also received a placebo nasal spray or placebo injection to preserve the double-blind design of the study. The trial included more than 6,300 previously unvaccinated children with nearly 50% of those children less than 2 years of age.

The overall incidence of adverse events and serious adverse events was similar in both groups except for a higher incidence of runny nose and nasal congestion in CAIV-T recipients (2.5 – 5.6% increase) and a higher incidence of injection site reactions in those receiving the flu shot (3.6 – 7.6% increase).