WASHINGTON (November 16, 2009)--The U.S. Food and Drug Administration is considering whether to approve an updated version of Pfizer's bestselling anti-infection vaccine for children, despite company studies that failed to meet certain goals.

The Prevnar 13 vaccine reduces risk of infection by 13 varieties of pneumococcal disease, which causes ear infections, meningitis and pneumonia.

The new version of the vaccine protects against six more varieties of the disease, but FDA reviewers say in online documents that company studies failed to meet effectiveness goals for three types of pneumococcal disease.

The FDA will ask a panel of outside vaccine experts to weigh in on the results at a meeting Wednesday.

The agency is not required to follow the group's advice, though it usually does.