Prevnar, the Pfizer vaccine that is under investigation in Japan , is widely used in children and the elderly in the U.S. to prevent infection by a bacterium that causes pneumonia and meningitis. Infants routinely receive the shot, starting at two months of age and ending at 15 months, with a fourth dose. The goal of immunization is to prevent infection with Streptococcus pneumoniae bacteria. About one in 20 people who contract pneumonia because of infection by S. pneumoniae die, according to the CDC; the death rate is about three in ten for those whose infection leads to meningitis. Like all medicines, the vaccine can cause side effects. About half of those who take the vaccine develop redness or pain near where the shot was given, and fewer than 1% develop more severe reactions, like fever or muscle aches, the CDC says. Severe side effects include wheezing, hives and a fast heartbeat. Public health authorities and pediatricians consider the vaccine safe overall. The initial version of the vaccine was studied in more than 18,000 children before the FDA approved it, and another 65,900 children afterward. The newest version of Prevnar was studied in another 7,400 children. No major safety issues were found, the CDC says. “We’ve seen a vast decrease in pneumococcal infections

once we started using Prevnar and avoided a lot of illness in children,” Alanna Levine, a pediatrician in Tappan, N.Y., who has been using the vaccine in her office daily for more than five years, tells the Health Blog. She says her young patients, aside from an occasional rash or fever, experience few side effects. ”From my experience, it has a good safety profile,” she says. The latest iteration of Prevnar, one that protects against the 13 most common strains of the infection-causing pneumococcal bacteria, went on sale in the U.S. last year. The earlier version — which is what’s used in kids in Japan –  was designed to ward off seven strains of the bacteria. Japanese authorities are also investigating whether Sanofi-Aventis’s ActHIB vaccine played a role in the four child deaths. The FDA approved the vaccine in 1993. It’s not as widely used as Prevnar, because there are competing Hib vaccines made by other companies. The CDC recommends all children in the U.S. under five years of age are immunized against the Hib bacteria, since infection can also lead to meningitis and pneumonia, and in rare instances can be fatal. Image: iStockphoto

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Scrutinized in Japan, Pfizer’s Prevnar Vaccine is Used Widely in U.S.