The World Health Organization (WHO) has called for the development of a vaccine against Group B streptococcus (GBS), a common bacteria implicated in the deaths of around 150,000 babies each year.
In their report, issued November 2, the WHO revealed the global burden of GBS is much higher than previously thought. As well as the aforementioned alarming number of newborn deaths, the bacterium is also linked to over half a million preterm births and at least 46,000 stillbirths a year – though the real numbers are likely even higher, as there are significant data gaps around the total burden of death and disease.
“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. WHO joins partners in calling for urgent development of a maternal GBS vaccine, which would have profound benefits in countries worldwide,” Dr Phillipp Lambach, Medical Officer from WHO’s Immunization, Vaccines and Biologicals department, and report author, said in a statement.
GBS is harmless for most who carry it. An average of 15 percent of pregnant people – nearly 20 million per year – carry the bacterium in their vagina. While this is usually asymptomatic, GBS can pass to babies during pregnancy, childbirth, or in the early weeks of life, which can be extremely serious. The bacterium is linked to neonatal and newborn meningitis and sepsis, both of which can be fatal, and can result in neurodevelopmental impairment and congenital defects.
Currently, antibiotic therapy is used to treat cases in infants and parents. Antibiotics are also used as a precaution to prevent GBS and are administered during labor to parents in whom the bacterium has been detected. However, the risk still remains high.
“Prevention of early onset GBS is possible in countries where it is policy,” Professor Joy Lawn, Director of the Maternal Adolescent Reproductive & Child Health (MARCH) Centre at London School of Hygiene & Tropical Medicine and contributor to the report told IFLScience. “However, even with high use of GBS test and treat in pregnancy, GBS stillbirths and GBS-associated preterm birth will not be likely to be prevented by antibiotics.”
This is the case across the world, but particularly in low- and middle-income countries, where the burden of GBS was the greatest. In sub-Saharan Africa, for example, rates of maternal GBS are the highest in the world – accounting for almost half of the global burden. Eastern and South-Eastern Asia are also disproportionally affected.
A preventative maternal vaccine, therefore, is urgently needed, the WHO says. Several candidates are in the pipeline, but none are available yet, despite almost 40 years of work.
“The idea for a maternal GBS vaccine was suggested about 4 decades ago, but is only in the last decade that more progress has been made,” Prof. Lawn told IFLScience.
“One hexavalent [six-in-one] vaccine is entering phase 3 trials in humans... Then following is a protein based one.” A few, including an mRNA vaccine, are in pre-clinical trials, she added.
Promising as this is, the report highlights the urgency of the situation and calls for vaccine developers and funders to accelerate the development of a safe and effective GBS vaccine. An estimated 50,000 GBS-related deaths, as well as over 170,000 preterm births, could be prevented every year if said vaccine reached 70 percent of pregnant people. The benefits would not only be health-focused but also financial – the report claims that between $1 billion and $17 billion could be saved worldwide from just a year of maternal GBS vaccination.
“A new maternal vaccine against GBS would be a game-changer in the reduction of newborn and maternal deaths for the most affected countries,” Dr Martina Lukong Baye, Coordinator of the National Multisector Programme to Combat Maternal, Newborn & Child Mortality at the Ministry of Public Health in Cameroon, said. “We plead to all stakeholders to treat this as a matter of moral priority.”