Response to Type III Polysaccharide in Women Whose Infants Have Had Invasive Group B Streptococcal Infection

Abstract

THERE is considerable mortality and morbidity in the United States from perinatal group B streptococcal disease.^{1 , 2} Approximately 3 neonates per 1000 live births, or an estimated 11,000 infants annually, have invasive group B streptococcal disease; two thirds of these infections are caused by the Type III capsular serotype.³ Pregnancy-related morbidity (e.g., urinary tract infection, chorioamnionitis, postpartum endometritis and bacteremia, and wound infections complicating cesarean section) affects approximately 50,000 women each year.^{2 , 3} One method proposed for the prevention of group B streptococcal disease in mothers and their infants is active immunization of women. This proposal is based on the observation that the susceptibility of infants to invasive infection with group B streptococcus is related to the acquisition of low (4 We have shown previously that vaccination of pregnant women with Type III polysaccharide of group B streptococcus results in placental transfer of IgG-specific antibody to the fetuses of women who responded to the vaccine (r = 0.913 for the correlation of pairs of maternal serum samples and infant cord-serum samples) and that these maternal antibodies persist in protective concentrations for two months in 72 percent of the infants.⁵ These findings suggest that vaccination could prevent infections with group B streptococcus in parturient women as well as in neonates.