Potential for Maternally Administered Vaccine for Infant Group B Streptococcus

This original research article reports on a phase 2, placebo-controlled trial evaluating a hexavalent glycoconjugate vaccine (GBS6) administered during pregnancy to protect infants against invasive group B streptococcal disease. The study included immunogenicity and safety assessments in pregnant women and their infants, alongside a parallel seroepidemiologic analysis to define protective thresholds for maternally transferred anti-capsular polysaccharide (CPS) IgG antibodies. GBS6 induced IgG responses in mothers against all six serotypes, which were transferred to infants at levels associated with a 75–95% reduction in disease risk. Safety signals were comparable across groups, though aluminum phosphate–adjuvanted formulations resulted in higher local reactogenicity. Antibody transfer ratios ranged from 0.4 to 1.3. These findings support GBS6’s potential to prevent both early- and late-onset GBS disease globally, particularly in settings lacking access to intrapartum antibiotic prophylaxis.

This original research article reports on a phase 2, placebo-controlled trial evaluating a hexavalent glycoconjugate vaccine (GBS6) administered during pregnancy to protect infants against invasive group B streptococcal disease. The study included immunogenicity and safety assessments in pregnant women and their infants, alongside a parallel seroepidemiologic analysis to define protective thresholds for maternally transferred anti-capsular polysaccharide (CPS) IgG antibodies. GBS6 induced IgG responses in mothers against all six serotypes, which were transferred to infants at levels associated with a 75–95% reduction in disease risk. Safety signals were comparable across groups, though aluminum phosphate–adjuvanted formulations resulted in higher local reactogenicity. Antibody transfer ratios ranged from 0.4 to 1.3. These findings support GBS6’s potential to prevent both early- and late-onset GBS disease globally, particularly in settings lacking access to intrapartum antibiotic prophylaxis.