‘Urgent’ need for Strep B vaccine to prevent baby deaths

WHO is calling for the for urgent development of vaccines against Group B streptococcus which kills almost 200,000 babies each year. Copyright:chuddlesworth(CC BY-NC-ND 2.0)

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  • Report reveals extent of global Strep B burden
  • Bacterium, also known as GBS, is linked to almost 150,000 baby deaths
  • Health institutions call for urgent development of vaccine

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The World Health Organization (WHO) has called for urgent development of vaccines against Group B streptococcus, also known as GBS or Strep B, as new figures reveal that the bacterium is responsible for 150,000 deaths ofbabiesworldwide each year.

The report by the WHO and the London School of Hygiene and Tropical Medicine (LSHTM) says the bacterium, which is harmless for most pregnant women who carry it, is linked to 46,000 stillbirths annually and more than half a million preterm deliveries. It can also cause long-term disability.

Several vaccine candidates are currently under development but none are yet available despite having been in the pipeline for decades, according to the WHO.

“Developing countries bear the highest burden of Strep B, which kills almost 200,000 babies each year, report shows.”

Joachim Osur, Vice Chancellor, Amref International University, Nairobi

Healthexperts say a maternal vaccine against GBS could be highly cost-effective and benefit all regions of the world, particularly low- and middle-income countries (LMICs) where the vast majority of cases occur.

“For the first time this new research quantifies the major contribution of GBS to pre-term births as well as neurological impairments, such as cerebral palsy, hearing and vision loss that can occur following GBS-associated infections,” said Philipp Lambach, a medical officer with the WHO’s vaccines and biologicals department who co-authored the study.

He said the research showed that Strep B is a major and unappreciated threat to newborn survival and wellbeing with devastating effects for families worldwide.

LMICs are particularly hard hit, the research shows, accounting for 98 per cent of cases.

Joy Lawn, directorof the Maternal Adolescent Reproductive and Child Health (MARCH) Centre at LSHTM and a contributor to the report, said: “Sub-Saharan Africa has a disproportionate burden, since Africa has 13 per cent of the world’s population and almost five per cent of burden of GBS deaths for newborns and stillbirths.”

Even more worrying, believes Lawn, is that health professionals often miss GBS cases whenever and wherever they occur. “Most midwives in the world will have seen cases but may not know if they are not being investigated,” she explained.

According to Joachim Osur, a reproductive health expert and Vice Chancellor at Amref International University in Nairobi, the problem could be even more pronounced in Africa than figures suggest.

“The problem in Africa is that due to weak health systems, we do not investigate causes of intrauterine or foetal deaths. We therefore do not know the causes,” explained Osur.

“This bacterium could be causing many deaths in our communities. The sooner we can get the vaccine, the better.”

平均15%的怀孕的我men worldwide—nearly 200 million a year—carry the GBS bacterium in their vagina, usually without symptoms, according to the report. It can be transmitted to the baby in the womb, during birth, or in the early weeks of life.

Currently antibiotic treatment given to women during labour are the main means of preventing GBS diseases in newborn infants, the study says.

如果在怀孕期间检测到细菌,怎么做ever, even in regions with high treatment coverage, there remain significant risks as this intervention is unlikely to prevent most GBS associated stillbirths, preterm births or GBS diseases that occur later after birth, it adds.

According to Martina Lukong Baye, coordinator of a national programme to combat maternal, newborn and child mortality at the Ministry of Health in Cameroon, a new maternal vaccine against GBS would be a game-changer in the reduction of newborn and maternal deaths for the most affected countries, especially in Sub-Saharan Africa.

Several vaccines are at phase two clinical trials, said Lambach, adding: “Some of them are multivalent, covering most of the major strains of GBS in pregnant women.”

But he added that vaccine development is complex and costly, particularly at late stage clinical trials, and there are uncertainties due to evidence gaps.

Assumptions about the severity of the disease as well as feasibility of implementation in low-resource settings may also have been preventing manufacturers from prioritising GBS vaccine development.

“The evidence and analysis in the report aim to help assure manufactures, [by] indicating that the disease burden is greater than previously assumed,” Lambach added. “And by suggesting that an affordably-priced vaccine is likely to be cost-effective, have a positive global net monetary benefit … and likely be financially sustainable and profitable if adopted in low-, middle-, and high-income countries.”

This piece was produced by SciDev.Net’s Global desk.