BACKGROUND: Multivalent conjugate Group B streptococcus (GBS) vaccines are in development for use in pregnancy. We aimed to understand perceptions of a novel GBS vaccine among pregnant and lactating persons following the COVID vaccine experience. METHODS: As part of an ongoing survey-based prospective cohort study, we conducted a follow-up survey with questions about GBS knowledge and acceptability of clinical trial participation for a novel GBS vaccine. Participants in this Institutional Review Board-exempt study completed surveys via REDCap survey online. RESULTS: Among 14,903 participants who completed the follow-up survey, 1785 were pregnant, 6661 were lactating and 6457 were either recently pregnant or lactating or planning for pregnancy. Pregnant individuals were less likely to report that they would likely or extremely likely participate in a clinical trial for a GBS vaccine during pregnancy compared with people who were neither pregnant nor lactating (P <
0.001). In contrast, lactating individuals were more likely to report that they would likely or extremely likely participate in a clinical trial for a novel GBS vaccine in lactation compared with people who were neither pregnant nor lactating (P <
0.001). Most participants preferred protein-based (n = 10,214, 70.5%) and mRNA-based (n = 10354, 71.5%) vaccine platforms for GBS vaccines. CONCLUSIONS: Overall, our participants expressed a good understanding of GBS. There is a mixed acceptability of participation in a novel GBS vaccine clinical trial during pregnancy with a greater acceptability during lactation. The perspective of pregnant and lactating people is critically relevant as new vaccines are developed.