Wits VIDA Globally Advances Maternal Vaccine to Protect Newborns from GBS
Wits VIDA plays central role in global effort to help protect newborns from sepsis due to Group B Streptococcus (GBS).
Researchers from the Wits Vaccines and Infectious Diseases Analytics (Wits VIDA) Research Unit at the University of the Witwatersrand (Wits) have played a leading role in a landmark international phase 1 / 2 clinical trial demonstrating the safety and immunogenicity of an investigational maternal vaccine against Group B Streptococcus (GBS) – a major cause of life-threatening infections in newborn babies worldwide. The findings have been published in Nature Medicine.
The study evaluated Pfizer’s investigational hexavalent Group B Streptococcus conjugate vaccine candidate (GBS6) in both non-pregnant women and pregnant women, together with their infants. The trial found that the vaccine was generally well tolerated, generated robust immune responses against all six clinically important GBS serotypes, and resulted in efficient transfer of GBS-specific antibodies from vaccinated mothers to their babies.
Wits VIDA was central to the implementation and successful conduct of the clinical trial. South Africa was the primary recruiting country, contributing the overwhelming majority of study participants across both the early and later stages of the trial, reflecting the country’s internationally recognised expertise in maternal and infant vaccine research.
Group B Streptococcus is one of the leading causes of neonatal sepsis, meningitis and pneumonia, accounting for approximately 300 000 serious infections, including 100 000 deaths, in young infants globally each year. The greatest burden of GBS disease in infants occurs in Africa and other low- and middle-income countries, with South Africa reporting among the highest incidence globally (approximately 2-3 cases for every 1000 births). Also, maternal GBS infection could predispose to preterm labour and stillbirths. Current prevention strategies based on intrapartum antibiotics have important limitations, particularly in resource-constrained settings, and do not protect against late-onset disease. Consequently, the WHO has designated a vaccine against GBS, to be given to women during pregnancy aimed at protecting their young infant, as a priority vaccine for development.
Professor Shabir Madhi, Director of Wits VIDA and one of the study’s senior investigators, said: “This publication represents another important milestone in the decades-long effort to develop an effective maternal vaccine against Group B Streptococcus. Maternal immunisation offers the opportunity to protect newborns during the most vulnerable first months of life, when they are at greatest risk of severe infection. These encouraging findings provide further evidence supporting continued development of this vaccine.”
The trial demonstrated comparable safety outcomes between vaccine and placebo recipients. Among pregnant participants, rates of adverse events, serious adverse events and delivery outcomes were similar between the two groups. Infants born to vaccinated mothers likewise had similar safety outcomes to those born to mothers receiving placebo. Importantly, vaccinated mothers developed high concentrations of antibodies that crossed the placenta efficiently, resulting in robust antibody levels in their infants at birth.
The publication builds on Wits VIDA’s longstanding leadership in vaccine research, which has contributed to the development and evaluation of vaccines against respiratory syncytial virus (RSV), rotavirus, pneumococcal disease, influenza virus, COVID-19 and now Group B Streptococcus. The unit continues to play a pivotal role in generating evidence that informs global maternal and child health policy.
The study also highlights the importance of South Africa’s clinical research infrastructure and its contribution to advancing vaccines designed to address diseases that disproportionately affect African populations.
While additional studies are required before the vaccine can be licensed, the results provide strong support for continued clinical development of maternal GBS vaccination as a strategy to reduce newborn deaths and severe infections worldwide.
Wits is currently enrolling in a phase 3 trial for GBS6 (NCT: NCT07160244).
About Wits VIDA
The Vaccines and Infectious Diseases Analytics (VIDA) Research Unit at the University of the Witwatersrand is one of the world’s leading centres for vaccine and infectious disease research. VIDA conducts internationally recognised clinical trials, epidemiological studies and translational research focused on reducing the burden of infectious diseases, particularly among mothers, infants and children in Africa. Its research has contributed to the development and implementation of several life-saving vaccines globally.
