Group B Streptococcus infection causes estimated 150,000 stillbirth, infant death

November 6, 2017

An estimated one in five pregnant women around the world carry Group B Streptococcus (GBS) bacteria which is a major, yet preventable, cause of maternal and infant ill health globally.

These are the findings of a new research supplement published in the journal Clinical Infectious Diseases, and launched at the American Society of Tropical Medicine and Hygiene Annual Meeting in Baltimore.

Led by the London School of Hygiene & Tropical Medicine and involving more than 100 researchers from around the world, the series of 11 research papers conservatively estimates that out of 410,000 GBS cases every year, there will be at least 147,000 stillbirths and infant deaths globally¹. Despite being home to only 13% of the world's population, Africa had the highest burden, with 54% of estimated cases and 65% of stillbirths and infant deaths.

This first comprehensive study of the burden of GBS, funded by a grant from the Bill & Melinda Gates Foundation, includes data and estimates for the year 2015 from every country of the world, including outcomes for pregnant women, their babies and infants. Previous data on GBS burden focused on infant cases and high-income countries, but the impact of GBS worldwide, especially in Asia, was less clear.

The new research found GBS is present among pregnant women in all regions of the world, with an average of 18% of pregnant women worldwide carrying (colonised with) the bacteria, ranging from 11% in eastern Asia to 35% in the Caribbean, totalling 21.7 million2 in 195 countries

The top five countries by numbers (to nearest 100) of pregnant women colonised were: India (2,466,500) China (1,934,900), Nigeria (1,060,000), United States of America (942,800) and Indonesia (799,100).

Although several vaccines to prevent GBS are in development, none is currently available. This is despite the disease accounting for more than the combined neonatal deaths from tetanus, pertussis, and respiratory syncytial virus, for which maternal vaccines are already in use, or further advanced in development. This analysis shows for the first time that a maternal GBS vaccine, which was 80% effective and reached 90% of women, could potentially prevent 231,000 infant and maternal GBS cases.

GBS is carried by up to a third of adults, usually with no symptoms. In women, GBS can live harmlessly in the digestive system or lower vaginal tract, from where it can be passed to the unborn baby through the amniotic fluid or to newborns during labour. Babies are more vulnerable to infection as their immature immune systems cannot fight off the multiplying bacteria. If untreated, GBS can cause serious infections, such as meningitis and septicaemia, which may lead to stillbirths, and newborn and infant deaths. If they survive, babies can develop permanent problems including hearing or vision loss, or cerebral palsy.

Current GBS prevention focuses on giving antibiotics to women in labour, aiming to reduce disease in infants at delivery. At least 60 countries have a policy for antibiotic use in pregnancy to prevent newborn GBS disease. Of those, 35 have a policy to test all pregnant women to see if they carry GBS, and the remaining 25 countries identify women with clinical risk factors. However, implementation of these policies varies around the world.

Joy Lawn, Series co-lead and Professor of Maternal, Reproductive and Child Health at the London School of Hygiene & Tropical Medicine, said: "Too many parents around the world face the death of a baby or a young child - avoidable GBS deaths are happening in every country. Antibiotics currently prevent an estimated 29,000 cases of early-onset Group B Streptococcal disease per year, almost all in high-income settings. However, this approach may be difficult in low-income settings where many births take place at home, and laboratory capacity for screening for GBS is limited. In addition, giving antibiotics to 21.7 million women may contribute to antimicrobial resistance - a major global health crisis."

Anna Seale, Series co-lead and Associate Professor at the London School of Hygiene & Tropical Medicine said: "Even if antibiotics were given to all pregnant women identified through screening strategies, they target mainly early-onset GBS disease in newborns, not GBS disease in pregnant , GBS disease before delivery causing stillbirth, or GBS disease in infants more than a couple of days old. A maternal GBS vaccine could prevent many more cases and deaths worldwide."

Dr Keith Klugman, Director of the Pneumonia Team at the Bill & Melinda Gates Foundation, said "The first few days and weeks of a baby's life are the most vulnerable - by far. By filling in one of the great voids in public health data, this work provides crucial insight and shows the pressing unmet need for the development of an effective Group B Strep vaccine. Immunizing expectant mothers is a potentially ground-breaking approach that could dramatically reduce the number of maternal and child deaths."

Johan Vekemans, co-author and Medical Officer, Initiative for Vaccine Research, World Health Organization, said: "These disease burden estimates highlight the importance of perinatal infection prevention. Existing recommendations should be implemented, but these are insufficient, and the number of affected families remain unacceptable. It is now essential to accelerate the GBS vaccine development activities. The technical feasibility is estimated to be high. Guidance highlighting research priorities is available. Work is ongoing to strengthen existing maternal immunization programmes. Next steps include a comprehensive evaluation of cost-effectiveness. We will be working with Professor Lawn and others at London School of Hygiene & Tropical Medicine, and global partners to lead on these activities."

Explore further: New study finds that vaccinating mothers against flu can protect newborns

More information: Clinical Infectious Diseases (2017). academic.oup.com/cid/issue/65/suppl_2

Related Stories

New study finds that vaccinating mothers against flu can protect newborns

June 2, 2016
Each year, influenza causes between 250,000 and half a million deaths around the world. Pregnant women and young infants have a higher risk of complications related to influenza; these complications can easily lead to death. ...

Women in preterm labour to be offered antibiotics to combat Group B Strep

September 18, 2017
Women who go into labour before 37 weeks of pregnancy should be offered antibiotics to prevent a possible transmission of Group B Streptococcal (GBS), according to updated guidance published by the Royal College of Obstetricians ...

Pregnant women asked to take part in a vaccine trial to tackle a severe baby disease

October 4, 2017
Expectant mothers in London are among the first in the world to participate in a clinical trial of a possible vaccine against a virus which causes life threatening breathing problems in babies.

Protecting newborns from pertussis

August 24, 2017
Dear Mayo Clinic: I am four months pregnant and live in an area where there has been a pertussis outbreak. What's the best way to keep my newborn baby safe until he or she can get the vaccine?

Better care can save 3-m babies, mothers per year, study reports

May 20, 2014
The lives of three million women and babies can be saved every year by 2025 for an annual investment of about a dollar per head in better maternity care, researchers said Tuesday.

Mothers with history of herpes can protect their offspring from neurological infection

July 5, 2017
Pregnant women with a previous history of herpes simplex virus type 1 (HSV-1) infection maintain active antibodies against the virus, and researchers have found that this protection can pass to the nervous systems of their ...

Recommended for you

Study opens new avenue in quest to develop tuberculosis vaccine

November 24, 2017
A team of scientists led by the University of Southampton has taken an important step forward in research efforts that could one day lead to an effective vaccine against the world's deadliest infectious disease.

Four simple tests could help GPs spot pneumonia and reduce unnecessary antibiotics

November 23, 2017
Testing for fever, high pulse rate, crackly breath sounds, and low oxygen levels could be key to helping GPs distinguish pneumonia from less serious infections, according to a large study published in the European Respiratory ...

New approach to tracking how deadly 'superbugs' travel could slow their spread

November 22, 2017
Killer bacteria - ones that have out-evolved our best antibiotics—may not go away anytime soon. But a new approach to tracking their spread could eventually give us a fighting chance to keep their death toll down.

Research points to diagnostic test for top cause of liver transplant in kids

November 22, 2017
Biliary atresia is the most common cause of liver transplants for children in the United States. Now researchers report in Science Translational Medicine finding a strong biomarker candidate that could be used for earlier ...

Alcohol consumption and metabolic factors act together to increase the risk of severe liver disease

November 22, 2017
A new study provides insights into the interaction between alcohol consumption and metabolic factors in predicting severe liver disease in the general population. The findings, which are published in Hepatology, indicate ...

Metabolites altered in chronic kidney disease

November 22, 2017
Chronic kidney disease (CKD) affects 1 in 7 people in the United States, according to the U.S. National Institute of Diabetes & Digestive & Kidney Diseases (NIDDK). These individuals have a very high risk of cardiovascular ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.