New vaccine may be responsible for delayed disease activity, fewer severe cases
MONDAY, June 30 (HealthDay News) -- The 2007-2008 rotavirus season began three months later than usual and has been significantly milder, suggesting that 2006 recommendations for infants to be vaccinated at ages 2 months, 4 months and 6 months with the RotaTeq vaccine may be having an impact, according to an interim report issued June 25 in the early release edition of the U.S. Centers for Disease Control and Prevention's (CDC) Morbidity and Mortality Weekly Report.
CDC researchers analyzed data from the National Respiratory and Enteric Virus Surveillance System and the New Vaccine Surveillance Network.
The researchers found that rotavirus activity started in February instead November and peaked at the end of April instead of March. They also found substantial reductions in the number of rotavirus-related hospitalizations, emergency department visits and physician visits. Between Jan. 1 and May 3, 2008, they observed that the number of laboratory tests for rotavirus was down by 37 percent, and that the number of tests that were positive for rotavirus was down by 78.5 percent.
"The changes appear to be greater than expected based on the protective effects of the vaccine alone," Anne Schuchat, M.D., director of the National Center for Immunization and Respiratory Diseases at CDC, said in a statement. "It is also possible that current levels of vaccination may be helping to decrease the spread of rotavirus to unvaccinated individuals in the community."
RotaTeq is manufactured by Merck & Co., Inc., Whitehouse Station, N.J.