What Are We Doing About Group B Strep Prevention?
Group B Strep (GBS) accounts for up to 3.5 million preterm births worldwide according to a 2017 study on GBS during pregnancy and early infancy. The number of stillbirths due to GBS infection is a bit harder to estimate accurately because often grieving parents refuse autopsy.
Even without those numbers, however, GBS is confirmed as the leading cause of infant disease, especially in the first week of life, accounting for life-threatening ailments such as pneumonia, sepsis and meningitis.
The US is among the top five countries by numbers of pregnant women carrying the bacteria, according to WHO. We at FindMeCure would like to take this opportunity to raise awareness during Group B Strep Awareness Month and take a look at what we’re doing to battle this global issue.
What about prevention?
It’s estimated that about one third of adults are carriers of the GBS bacteria that is often asymptomatic and can live undisturbed in the digestive tract – or as is the case with women – the lower reproductive tract where it can infect the baby in-utero or be passed to the newborn in the birth canal during delivery.
So far, we rely on prevention via screening and antibiotics during labour. 60 countries have a policy of using antibiotics during pregnancy. What this often means is that an expecting mother is administered antibiotics for at least 4 hours before labour in order to prevent infecting the infant during birth.
35 of those 60 countries have a screening policy in place. In the US for example testing for GBS at 37 weeks is the standard, though doctors recommend early testing for anyone who wants to lean on the safe side.
Pregnant women should also keep in mind that GBS is a sneaky bacteria and one negative test result is not usually enough to eliminate the possibility of GBS colonisation and additional tests should be carried out later on.
This is not an ideal solution, however. The use of antibiotics during delivery only prevents an estimated 29 000 infants being infected with GBS a year and it’s not a good enough option in the developing countries, where most births take place at home and labs are too overwhelmed to be able to provide regular screenings.
This is not the only reason antibiotics are not a sustainable solution on a global scale, of course. We’ve already discussed here on the blog the antibiotic crisis that is already upon us. According to Joy Lawn, Professor of Maternal, Reproductive and Child Health at the London School of Hygiene & Tropical Medicine, giving antibiotics to 21.7 million women worldwide (the estimated number of expecting mothers who carry GBS) can contribute to the bacteria building resistance and becoming harder to kill both in pregnant women and in infants in case of infection.
Is there a vaccine?
Professionals in the field advocate for a vaccination policy implemented on a global scale, as this is by far the best solution in both wealthy settings and in countries with a developing economy.
Several vaccines against GBS are now in development, but none is available yet. According to WHO such a vaccine should be a bigger priority than it is now, as it can prevent 231 000 infant and maternal GBS cases if it reaches 90% of women and is 80% effective.
In the fight against GBS two strategies can be employed when developing vaccines. One is developing polysaccharide conjugate vaccines – a type a vaccines made by attaching a poor antigen to a strong one in order to provoke a strong response by the immune system against the poor antigen, which is often a polysaccharide, hence the name, while the other one, the strong antigen, is a protein.
The other path researchers can take is developing recombinant protein vaccines – these vaccines are made by inserting the DNA of an antigen that provokes an immune system response into bacterial or mammalian cells.
By 2015 according to the NCBI only polysaccharide-based vaccines had been tested in clinical trials. If you see this as a worthy cause and you’d like to speed up the process of developing new prevention and treatment methods for GBS, you can search for clinical trials in our database. We’d all like to see GBS eradicated and we hope by raising awareness we inspire more people to take action.