CDC Releases Report on Early- and Late-Onset Neonatal GBS Infection

In 2002 the Centers for Disease Control and Prevention (CDC), the American College of Obstetricians and Gynecologists, and the American Academy of Pediatrics recommended universal screening of pregnant women at 35 to 37 weeks’ gestation for rectovaginal group B streptococcus (GBS) colonization; intrapartum antimicrobial prophylaxis was recommended for carriers. To assess the impact of this strategy, the CDC analyzed data from 1996 to 2004 from the Active Bacterial Core surveillance system. The report was published in the December 2, 2005, issue of Morbidity and Mortality Weekly Report and is available athttp://www.cdc.gov/mmwr/preview/mmwrhtml/mm5447a2.htm.

The data represented approximately 337,000 live births in 1996 to approximately 427,000 live births in 2004. GBS found in children between zero and six days of age was defined as early onset, and disease found in children between seven and 89 days of age was considered late onset. The CDC found that the incidence of early-onset GBS infection in 2004 decreased 31 percent from 2000 and 2001, the period just before the universal screening was implemented. The incidence of late-onset GBS infection remained the same from 1996 to 2004.

Although the absolute difference between blacks and whites in the incidence of early-onset infection declined 68 percent from 1993 (before the prevention guidelines were released) to 2003, racial disparities still exist. In 2004, the rates of late-onset GBS infection per 1,000 live births were 0.83 for blacks, 0.28 for whites, and 0.19 for infants of other races. Similarly, the rates of early-onset disease per 1,000 births were 0.73 for blacks, 0.26 for whites, and 0.15 for other races.

In both early- and late-onset GBS infection, the fatality ratio was highest for preterm infants (23 percent of infants with early-onset infection and 9 percent of those with late-onset infection). Of term infants, 4 percent with early-onset infections died, whereas no infants with late-onset infection died. Continued examination is needed to evaluate the effects of the 2002 guideline revision on early-onset infections and to determine the long-term effects of intrapartum use of antimicrobial agents on neonatal GBS infection.