Garden City

Researchers are evaluating the safety and immune response of a group B streptococcus (GBS) vaccine in healthy pregnant women and their babies in this Phase 3 randomized, placebo-controlled, double-blinded trial. The study includes pregnant women aged 49 or younger between 24 and 36 weeks of gestation with uncomplicated singleton pregnancies and no major fetal abnormalities. Participants must also have documented negative tests for HIV, syphilis, and hepatitis B during this pregnancy. The goal is to learn how the vaccine works and to monitor safety for both mothers and their infants. Participants will receive one injection of either the GBS6 vaccine or a saline placebo. Pregnant women will be followed for up to 14 months, including 6 months after delivery. Their babies will be followed for about 12 months after birth. A subset of infants will also receive routine vaccinations such as diphtheria toxoid-containing vaccines and pneumococcal vaccines according to their country's immunization schedule, with blood samples collected one month after completing primary and toddler booster doses. Mothers will be monitored for local and systemic reactions within 7 days after vaccination, adverse events through 1 month, and serious or medically attended events up to 6 months postpartum. Infants will be observed for adverse events from birth through at least one year, with serious and medically attended events tracked through 6 months. Researchers will also measure antibody levels in infants at birth to assess the vaccine's potential to protect against early and late onset GBS disease. Mothers will attend at least 3 to 4 study visits, some via telephone, to support ongoing safety and immunogenicity assessments.