Maternal and Neonatal Immunisation

Vaccination during pregnancy is important for protecting both mother and baby against severe disease. At OVG we are part of large international consortia dedicated to developing maternal vaccines and expanding access for those who need them most.

Vaccines given during pregnancy generate maternal antibodies that are passed to the foetus and protect infants against infection. An understanding of maternal antibody decay is important when planning most infant vaccination schedules. Maternal antibodies decay in the first few months of life but if high levels of antibody persist these can interfere with the immune response to infant vaccinations. We have conducted multiple studies investigating the decay of maternal antibodies and explored how these interfere with vaccine responses in early life.

Maternal antibody decay is even more important when planning measles vaccine programmes as the degree of interference can be large. We are conducting a randomised clinical trial in Uganda to determine if early administration of measles-rubella vaccine at 6 months of age might protect more infants against severe infection than waiting until nine months of age. Due to high levels of maternal antibodies, measles vaccines are not recommended until at least nine months of age. High levels of severe measles-related illness in very young infants have led some countries to revise their vaccination policy, from the minimum nine months recommendation to an earlier start at six months of age. Our study will show if this early policy is a good idea.

OVG is also at the forefront of research into maternal group B streptococcus (GBS) vaccines. GBS is a leading cause of neonatal sepsis and meningitis as well as stillbirth and preterm birth and there is no licensed vaccine yet available. We are working to understand protective levels of antibody (“correlates of protection”) for GBS from large case-control studies in order to guide regulatory decision-making. We are also part of two major EDCTP-funded programmes of work to inform and accelerate GBS maternal vaccine development and licensure in Africa: