Step up vaccines against Group B strep, linked to baby deaths and disability

Group B streptococcus (GBS), which can be transmitted in the womb, is linked to around 150,000 deaths of babies each year, more than half a million preterm births and significant long-term disability.

The report by the World Health Organization (WHO) and the London School of Hygiene & Tropical Medicine (LSHTM) updates estimates from 2017, revealing that the global burden of GBS is much higher than previously recognized.

“This new research shows that Group B strep is a major and underappreciated threat to newborn survival and wellbeing, bringing devastating impacts for so many families globally,” said Dr, Phillipp Lambach, Medical Officer from WHO’s Immunization, Vaccines and Biologicals department.

For the first time, the report quantifies the major contribution of GBS to preterm births, and to neurological impairments such as cerebral palsy, hearing and vision loss, that can occur following infection.

A mother’s loss

Around 15 per cent of all pregnant women worldwide, nearly 20 million annually, carry the GBS bacterium in their vagina, usually without symptoms. It can then spread to an unborn baby in the womb, or to newborns during labour.

Currently, the main way to prevent GBS disease in newborns is to administer antibiotic prophylaxis to women during labour, if the bacterium is detected during pregnancy.

However, significant health risks remain, even in regions with high prophylactic coverage, as this intervention in unlikely to prevent most GBS-associated stillbirths, preterm births, or GBS disease that occurs later after birth.

“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,” said Debbie Forwood, whose daughter Ada was stillborn after she developed a GBS infection.

Develop vaccines now

The largest burden of GBS is in low and middle-income countries, where screening and treatment are most challenging to implement. The highest rates of maternal GBS are found in sub-Saharan Africa, and in Eastern and South-Eastern Asia.

Now is the time for action, said Joy Lawn, an LSHTM Professor who contributed to the report.  Several candidate GBS vaccines are currently in development, but none are yet available, even though they have been in the pipeline for decades.

“Group B strep infection poses a serious challenge to every family affected, and in every country, said Ms. Lawn, Director of the university’s Maternal Adolescent Reproductive & Child Health (MARCH) Centre.

“Maternal vaccination could save the lives of hundreds of thousands of babies in the years to come, yet 30 years since this was first proposed, the world has not delivered a vaccine.”

Joy and sadness

The report calls for stepping up development of an effective GBS vaccine that could be administered to expectant mothers during routine pregnancy checkups.

The partners estimate more than 50,000 GBS-related deaths, and over 170,000 pre-term births, could be avoided if over 70 per cent of pregnant women were vaccinated.

Such protection could also be highly cost-effective, they added.  Net benefits from a year of maternal vaccinations could reach as high as $17 billion, accruing over several years, provided doses are affordably priced. For Ms. Forwood, this would be a bittersweet development.

“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,” she said.

“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.”