Researchers in the UK and affiliated with the World Health Organization are sounding the alarm over a common bacterium that can seriously harm pregnant people and their babies. In a new report released this week, the group estimates that infections caused by group B streptococci were linked to 46,000 stillbirths, 91,000 newborn deaths and over half a million premature births worldwide last year. The numbers are terrible enough for the WHO and partners to be calls for a maternal vaccine to prevent the bacterial disease.
Group B streptococci, or group B strep, are round bacteria that typically cluster together into single-line chains. Although there are seven broad groups of streptococcal bacteria, there is only one known bacterial species belonging to group B, called Streptococcus agalactiae. These bacteria are routinely found in the intestines and vaginas of up to a third of humans (as well as some animals) and it does not usually cause disease.
During pregnancy, however, the bacteria can migrate to other parts of the body, such as the urinary tract. It can also be transmitted to a fetus in the womb or to a newborn during childbirth or the first weeks of life. Urinary tract infections in the parent can increase the risk of premature birth, while infections in the placenta and amniotic fluid increase the risk of premature births, stillbirths, newborn deaths and congenital defects. In infected newborns, the bacteria can cause sepsis, a widespread inflammation that overwhelms the body and can quickly become fatal.
The infection has long been known as a common cause of sepsis in newborns. But in 2017, researchers from the London School of Hygiene & Tropical Medicine, WHO and others made the first attempt to quantify its global damage. The estimated that about 150,000 stillbirths and newborn deaths a year could be attributed to group B strep. This new report, led by the same groups, is the first to measure the number of premature births, which not only increases the risk of newborn death, but also long-term complications such as stunted development and congenital defects.
In all, they estimated that around 20 million pregnant women would be colonized with group B strep by 2020, putting them at risk for a serious infection. Estimates of stillbirths and newborns in 2020 were about the same as in 2017. But they now estimate that these infections contributed to 518,000 premature births by 2020. The bacteria infected nearly 400,000 newborns and about 40,000 were estimated to be left behind. with neurological impairment due to infection. Although the bacteria are found everywhere, pregnant women and their children in low- to middle-income countries were the most likely to be harmed by the infection, especially in Africa.
“This new research shows that group B strep is a major and underestimated threat to newborn survival and well-being, bringing devastating consequences to so many families globally,” said Phillipp Lambach, MD of the WHO Department of Immunization, Vaccines and Biology, in a announcement from the WHO, which publishes the report.
Pregnant women who test positive for group B strep are now given prophylactic antibiotics to prevent the transmission of newborns. However, experts note that antibiotics are not able to prevent most cases of stillbirth and premature birth associated with the infection, nor are they without side effects.
The most promising long-term solution to group B strep, the report’s authors say, is a vaccine that can be given to humans early in pregnancy. They estimate that an effective vaccine given to even 70% of pregnant women would prevent about 50,000 deaths and over 170,000 premature births a year. Depending on the price of a vaccine, it will probably also save money along the way, they add. But even though there are several experimental vaccine candidates in the research pipeline, efforts have been fruitless for decades at this time.
“Maternal vaccination could save the lives of hundreds of thousands of babies in the coming years, yet 30 years since it 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, ”said Joy Lawn, director of the Maternal Adolescent Reproductive & Child Health Center at the London School of Hygiene & Tropical Medicine, in the WHO statement.