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A vaccine for Group B Strep could be on the way, researchers say

pregnant woman getting a vaccine group b strep
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If you’ve been pregnant before or are approaching your third trimester,  you’ve likely heard the term “Group B Strep” bandied about. Medical experts don’t actually know why some women have this bacteria and others don’t, but it is incredibly common, affecting as many as 1 in 5 pregnant women.

The bacteria that’s behind Group B Strep (GBS), Streptococcus agalactiae, is relatively harmless to women, but it can be dangerous for infants. That’s why doctors test for it during the third trimester. If you test positive, the doctor typically gives you antibiotics during labor and delivery so it can’t harm your baby. The antibiotics work to stop the spread of the infection.

But getting routine antibiotics for GBS may one day change, because researchers are trying to come up with a GBS vaccine to protect against infection.

Scientists from Binghamton University recently published an article on their research in Infection and Immunity. 

“This research has identified and characterized a novel protein that could serve as a vaccine candidate to fight a bacterium that impacts women’s reproductive health and neonatal outcomes,” said Lamar Thomas, one of the researchers and a a postdoctoral fellow now at the University of California, San Diego, in the Department of Pediatrics. “I hope this work will inspire others to explore other novel proteins and microbial agents that may potentially aid in improving global health.”

When most people think of “strep,” they associate it with Streptococcus pyogenes (aka Group A Strep or GAS)—the type that causes strep throat.

There are many other pathogenic species of Streptococcus, including GBS and Streptococcus pneumoniae, which can be harmful (especially in the elderly), the researchers said.

GBS can pass onto babies in utero, with the potential to cause preterm birth. After birth, it can pass through close contact. Those infections are rare. Most of the time, the bacteria passes to the baby during birth. In the US, GBS infection is the leading cause of meningitis and blood infections in infants within the first three months of life.

The World Health Organization (WHO) estimates that infections caused by GBS in pregnant women are linked to 150,000 preventable stillbirths and infant deaths worldwide each year. Current guidelines recommend antibiotics for mothers who test positive for GBS, which have drastically lowered the rate of GBS, but the WHO is prioritizing a vaccine to help reduce risk as well.

The bacteria forms a biofilm that enables it to stick to each other and our bodies. The researchers targeted BvaP, a protein in the biofilm. The team said that blocking proteins including BvaP could be key to developing a vaccine that works to combat infection.

The team continues to try to understand more about BvaP. Even if BvaP does not prove to be the pathway that works to create a vaccine, the team is looking at how colonization works so they can come up with treatments against bacterial pathogens.

So while antibiotics to treat GBS are still useful, the hope is that women could one day receive a vaccine that makes GBS infection risk closer to zero.