Preparing for Group B Streptococcus Vaccine: Global perspectives on maternal immunisation

There are vaccines in clinical trials that target the bacterium Group B Streptococcus (GBS). Group B Streptococcus is a leading global cause of sepsis and meningitis in young infants. GBS is estimated to cause nearly 100,000 newborn deaths and 50,000 stillbirths per year globally, and GBS infection is an important cause of long term neurodisability. Group B Streptococcus vaccines are intended to be given to pregnant women to prevent infection in their infants. The success of any vaccine will depend on its uptake in the target population. Experience with prior maternal vaccines, e.g. influenza and COVID-19 vaccines, teaches us that acceptance of vaccines, especially if novel, is challenging for pregnant women. The objective of this thesis is to identify potential facilitators and barriers to acceptance of a future antenatal GBS vaccine across different healthcare settings. Research in three countries; the United States (US), Ireland and the Dominican Republic (DR) investigates how current maternal immunisation practices and approaches to GBS management during pregnancy may influence how a GBS vaccine might be accepted and integrated into routine antenatal care in different regions. I present the results of four studies: i) a narrative synthesis of the global literature on facilitators and barriers to maternal immunisation ii) a mixed methods survey and discrete choice experiment with 502 pregnant women in the US and Ireland iii) a survey with 300 pregnant women in the DR, and iv) a multicentre qualitative study with 70 maternity care providers in the US, Ireland, and the DR. Knowledge of GBS was poor among pregnant women in all three countries, 53% of US women, 30 % of Irish women and 1.7 % of DR women reported both an awareness and understanding of GBS. Pregnant women placed most importance on perceived infant benefit and provider endorsement when considering a future GBS vaccine. Among health care providers interviewed, there was variability in knowledge and beliefs pertaining to GBS, maternal vaccines and approaches to vaccine communication. Knowledge and beliefs differed by country and by provider type and impacted strength of provider endorsement of maternal vaccines. When considering novel vaccines, such as a GBS vaccine, pregnant women will be guided by their maternity care providers. However, this guidance may vary between providers. Taken together the results in this thesis highlight an urgent need for the inclusion of vaccinology, including content, specifically related to maternal immunisation, in the undergraduate, postgraduate and professional competence training of all healthcare professionals caring for pregnant women.