In 2014, the World Health Organization (WHO) convened the first meeting of the Product Development for Vaccines Advisory Committee. GBS was identified as one of the pathogens with a high burden among neonates and infants that may be amenable to prevention by immunization. In April 2016, a WHO consultation was held on GBS vaccines, concentrating on the development of vaccines for maternal immunisation.
Studies show that a GBS vaccine given to pregnant women may prevent 231,000 baby and mother cases each year.This could potentially prevent most cases of GBS without the need for antibiotics or screening.Babies would still be tested and treated for GBS if they developed symptoms.
A number of GBS vaccines are being developed throughout the world. A study has shown that mothers’ can pass different strains of GBS antibodies to their baby, depending on what they have been exposed to, and that this can provide protection to their baby after birth. This is important as it helps researchers know that a successful GBS vaccine could pass on protection from mother to baby, and has the potential to prevent this disease in newborns.
Furthers studies, such as PREPARE https://gbsprepare.org/seek to estimate the level of antibodies required for protection against the major GBS types causing disease across European and African sites. This could help to inform what is required of the vaccine.
GBS vaccines have been tested in animals, and in phase I and II trials in adults. These include a recent GBS vaccine that was given to non-pregnant women, with results indicating that the vaccine delayed carriage of the bacteria, with no safety concerns (GBS6). This needs to be assessed in pregnant women to see whether the antibodies would be passed on to provide protection for the baby. Some new vaccines have also been tested in pregnant women, and these have not been found to cause any problems during pregnancy. See for example a study by South African researchers from 2016.
For more information about vaccines in pregnancy, see also Vaccines in Pregnancy.
For information about GBS in pregnancy and newborns, see Patient information leaflet.
More information about Group B Streptococcus can be found on the Group B Strep Support charity website.