The rate of infants born with group B strep was 0.32 per 1,000 live births in 2003, the Centers for Disease Control and Prevention said. That is a drop of nearly 40 percent from 2000, when the rate was 0.52 per 1,000.
Group B strep is the most common cause of blood infection and meningitis in newborns. It also causes pneumonia. About 1,700 U.S. babies younger than a week old had the disease in 2001, the CDC said.
Between 1999 to 2001, the rate averaged 0.47 cases per 1,000 live births. The rate dropped after the CDC and the American College of Obstetricians and Gynecologists issued guidelines on the disease in 2002.