The incidence of early-onset neonatal group B streptococcal disease in the United States has dropped by a third since guidelines for universal screening of pregnant women were issued, the Centers for Disease Control and Prevention reported.
The guidelines, which call for routine screening of pregnant women for rectovaginal group B streptococcal (GBS) colonization at 35–37 weeks' gestation and administration of intrapartum antimicrobial prophylaxis to carriers, were jointly issued in 2002 by the American College of Obstetricians and Gynecologists, the American Academy of Pediatrics, and the CDC (MMWR Recomm. Rep. 2002;51[RR-11]:1–22).
In 2004, the incidence of GBS disease in newborns aged 0–6 days (early-onset disease) had decreased by 31% from the period of 2000–2001, immediately before universal screening was implemented, the CDC said (MMWR 2005;54:1205–8).
Late-onset GBS disease—occurring in infants aged 7–89 days—did not change during 1996–2004, the period for which data were analyzed from the CDC's Active Bacterial Core surveillance (ABCs) system. The ABCs areas represented approximately 337,000 live births in 1996 and 427,000 live births in 2004. A total of 308 cases of neonatal GBS disease were reported in 2004, 47% early-onset and 53% late-onset. Overall, 55% with neonatal GBS disease were white, 42% black, and 3% other races; 51% were female.
Among early-onset cases with complete data, the proportion born at less than 37 weeks' gestation increased significantly, from 20% (40 of 204) in 2000 to 29% (41 of 141) in 2004. Among late-onset cases with complete data in 2004, 55% (81 of 147) were born preterm. Case-fatality ratios were consistently higher among preterm infants, both in the early- and late-disease groups. Nine of the 40 preterm infants with early-onset disease died (23%) vs. none of the 66 term infants with late-onset GBS.
The rate of late-onset disease surpassed that of early-onset disease for the first time in 2003, a trend that continued in 2004. Racial disparities in the incidence of both early- and late-onset GBS disease persisted: In 2004, rates of early-onset disease were 0.73 per 1,000 live births for black infants vs. 0.26 per 1,000 for white infants. For late-onset disease, those rates were 0.83 per 1,000 live births for black infants vs. 0.28 per 1,000 for whites.