Review on the association of Group B Streptococcus capsular antibody and protection against invasive disease in infants

A trivalent Group B streptococcus (GBS) polysaccharide-protein conjugate vaccine for vaccination of pregnant women is under development to protect their newborns against invasive GBS disease. Establishing sero-correlates of protection against invasive GBS disease in infants could expedite the licensure pathway of polysaccharide-protein conjugate vaccine. A systematic review of studies reporting on the association of capsular antibodies and invasive GBS disease in infants and colonization in women or newborns was undertaken. Most studies that described maternal and/or infant capsular antibody levels in infants with invasive GBS disease identified an association between low capsular antibody levels in invasive GBS cases compared to controls. Different assay methods and the lack of standardized reference ranges for serotype-specific antibody levels makes it difficult to select an antibody level that may be used as a reliable sero-correlate of protection. Further studies using standardized methods are warranted.