A vaccine to protect newborns against Group B streptococcus (GBS) is moving closer to reality, with two leading vaccine candidates now in late-stage clinical development. Global health organizations are also working with countries to strengthen healthcare systems and prepare for the introduction of maternal GBS vaccination programs once a vaccine receives regulatory approval.
Group B streptococcus is a common bacterium that is usually harmless in adults but can be transmitted from mother to baby during pregnancy or childbirth. In newborns, the infection can cause severe illnesses such as sepsis, meningitis, and pneumonia, while survivors may experience lifelong disabilities, including hearing loss, blindness, and developmental delays. GBS infection during pregnancy is also associated with an increased risk of preterm birth and stillbirth.
According to global estimates, around 20 million pregnant women carried GBS in 2020, leading to approximately 393,000 invasive infections in infants, 91,000 infant deaths, 46,000 stillbirths, and more than 500,000 preterm births. The highest burden is in sub-Saharan Africa, where more than half of global GBS infections and nearly two-thirds of related infant deaths occur.
Two vaccine candidates are currently leading development efforts. One candidate, developed by Pfizer, targets six major GBS serotypes and is undergoing a Phase 3 clinical trial involving thousands of pregnant women across multiple countries. Another candidate, developed by MinervaX, is expected to begin Phase 3 trials later this year and is designed to provide broad protection against multiple GBS strains. Both vaccines are intended to be administered during pregnancy, allowing protective antibodies to pass from mother to baby before birth.
Because severe GBS infections in newborns are relatively uncommon and difficult to diagnose, researchers and global health organizations are pursuing an alternative regulatory pathway based on immune responses rather than waiting to measure disease outcomes directly. This approach could accelerate vaccine approval while maintaining strict safety and effectiveness standards.
Health organizations are also preparing countries for future vaccine introduction by strengthening maternal immunization programs, improving antenatal care services, training healthcare workers, and increasing public awareness. These preparations build on ongoing efforts to introduce maternal vaccines against respiratory syncytial virus (RSV), creating stronger healthcare systems that can support multiple maternal vaccination programs.
If successfully licensed and recommended, a maternal GBS vaccine could significantly reduce newborn infections, stillbirths, and infant deaths while improving health outcomes for families worldwide, particularly in low- and middle-income countries where the disease burden remains highest.
