Urgent Call for Maternal Group B Streptococcus Vaccine

Dawn O'Shea

November 04, 2021

A new report from the World Health Organisation (WHO) and the London School of Hygiene & Tropical Medicine (LSHTM) is calling on researchers, vaccine developers and funders to accelerate development of an effective vaccine against group B Streptococcus (GBS) that could be administered to pregnant women during routine pregnancy check-ups.

The Group B Streptococcus Vaccine: full value vaccine assessment report, for the first time, quantifies the enormous impact of GBS on neonatal and maternal mortality and morbidity. It states that the global burden of GBS is far higher than previously recognised, and includes neonatal meningitis, sepsis, death, neurodevelopmental impairment, preterm birth, and maternal sepsis. The infection has been linked with more than half a million preterm births annually, along with almost 100,000 neonatal deaths, at least 46,000 stillbirths, and significant long-term disability. In 2020, an estimated 19.7 million pregnant women were colonised with GBS and 390,000 infant GBS cases were estimated. An estimated 40,000 infants were living with neurological impairment following GBS-associated infections. The highest burden is in sub-Saharan Africa and South Asia.

However, the report also highlights gaps in the epidemiological data on GBS which create uncertainty around the total burden of deaths and disease. Infectious causes of stillbirths, for instance, are often under-investigated across countries, meaning the true contribution of GBS may be even higher still.

Vaccination could result in substantial declines in global morbidity and mortality due to GBS. Several GBS vaccine candidates are in development but none are yet available, despite having been in the pipeline for several decades.

Serious Challenge

Professor Joy Lawn, Director of the Maternal Adolescent Reproductive & Child Health (MARCH) Centre at the LSHTM, and a contributor to the report, said: "Group B strep infection poses a serious challenge to every family affected, and in every country. 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. Now is the time to act to protect the world’s most vulnerable citizens with a GBS vaccine."

Estimates suggest that if GBS vaccination reached over 70 per cent of pregnant women, more than 50,000 GBS-related deaths could be averted annually, as well as over 170,000 preterm births.

The WHO/LSHTM report says a maternal vaccine is likely to be a cost–effective intervention, with a positive global net monetary benefit, if the vaccine is affordably priced. It further states that GBS vaccine development is financially sustainable and is likely to be profitable for the manufacturer if it is adopted in high-income countries.

According to the report, the net monetary benefits from a year of maternal GBS vaccination could reach as high as £12.4 billion ($17 billion) over several years, if the vaccines are affordably priced.

The report was launched at the 2nd International Symposium on Streptococcus Agalactiae Disease (ISSAD) being hosted by the WHO and the LSHTM. This year the conference is taking place virtually from the UK from Wednesday 3 November to Friday 5 November 2021.

This article originally appeared on Univadis, part of the Medscape Professional Network.


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