SA leads vaccine efforts to save the lives of 100,000 newborns annually

South Africa is taking the lead in the development of a maternal vaccine against group B Streptococcus (GBS), which can kill newborns and cause maternal complications.

Vaccinology expert Prof Shabir Madhi, dean of health sciences at Wits University, said SA is the country worst affected by group B strep bacteria, which kills nearly 100,000 newborns across the globe annually.

“SA has consistently reported the highest burden of invasive group B Streptococcus disease in the first three months of life compared to any other country globally for the past 20 years," said Madhi, who was part of an international research project that recently found GBS infections are much more common than previously thought.

"Part of the reason for this is that infants born to women living with HIV are at three- to four-fold greater risk of developing invasive GBS disease such as blood and brain infections.”

After being passed to newborns during labour and delivery, GBS can cause serious invasive infections, including meningitis, bacterial pneumonia, and sepsis.

This week, public health experts from the World Health Organisation (WHO) and the London School of Hygiene & Tropical Medicine called for the urgent development of new vaccines to save the lives of newborns exposed to GBS.

Madhi's research team found the bacterium is common and usually harmless in pregnant women. But it is linked to more than half-a-million preterm births annually. Almost half of the babies it kills are stillborn.

GBS also causes 37,000 cases annually of neurodevelopmental impairment, including cerebral palsy and hearing and vision loss.

Although the bacteria was once thought to mostly affect wealthier nations, researchers said  its impact is seen mostly in low- and middle-income countries – mainly in Africa and  east and southeast Asia.

Madhi said the rate of invasive GBS disease in SA is about three in 1,000 children “of whom 20% go on to die, and 20% to 30% develop sequelae”.

It is against this backdrop that the SA Medical Research Council vaccines and infectious diseases analytics research unit, which Madhi leads, is conducting clinical trials towards the development of a GBS vaccine.

“We are currently undertaking the first trials of two new GBS vaccines at my unit in pregnant women," Madhi told TimesLIVE.

"We have been studying GBS for the past 15 years, including its epidemiology and understanding what immune responses vaccines should induce to protect the babies against GBS by vaccinating their mothers during pregnancy.

“We have also shown that one out of every 20 stillbirths in SA is due to GBS, and there is some evidence to indicate that GBS infection in the mother may predispose to preterm birth, which to is a common underlying cause of death in early infancy.”   

 Antibiotic therapy is the primary treatment for suspected and confirmed GBS infections in infants and mothers.

In women, the bacteria colonises in the vagina and rectum, and can ascend into the amniotic sac and infect babies before they are born.

“About one-third of women will be colonised during pregnancy, but only a minority of their babies go on to develop invasive GBS disease," said the researchers.

"However, it’s generally difficult to predict which babies will develop the disease. By vaccinating the pregnant women, there would be protection against GBS infection in the mother, who can also develop illness, as well as protection of the foetus against stillbirth or being delivered prematurely.”

The report says the development of a GBS vaccine would reduce deaths and could be highly cost-effective, with significant health benefits in all regions of the world.

Dr Phillipp Lambach, a lead author and medical officer from the WHO’s immunisation, vaccines, and biologicals department, said the new research “shows that Group B strep is a major and under-appreciated threat to newborn survival and wellbeing, bringing devastating impacts for so many families globally”.

He added: “We have also shown that one out of every 20 stillbirths in SA is due to GBS, and there is some evidence to indicate that GBS infection in the mother may predispose to preterm birth, which is a common underlying cause of death in early infancy."   

Estimates suggest that if vaccination reached over 70% of pregnant women, half of  GBS-related deaths could be averted, as well as more than 170,000 preterm births.

Debbie Forwood, whose daughter Ada was stillborn after she developed a GBS infection, said: “It is difficult to describe the breadth or depth of the grief when your child dies, or the accompanying guilt, and how it changes you, your family, and your relationships forever.

"Only a GBS vaccine could have saved Ada. When a vaccine can be widely rolled out, I will weep and scream with the unfairness that it came too late for her, and for all the other babies who are needlessly suffering and dying every year that it is delayed.

"But I will also weep with joy that in the future, many more will live, and their families will be saved from the living hell that is the death of a child."

TimesLIVE