Abstract
Background: Respiratory syncytial virus (RSV) is a leading cause of lower respiratory tract infections (LRTI), with significant morbidity and mortality in infants. In August 2023, the Pfizer RSVpreF vaccine was approved in the United States for maternal immunization, aiming to reduce RSV-related illness in neonates. The RSVpreF vaccine has proven efficacy in preventing severe LRTI in infants however, limited research exists on its potential side effects particularly on maternal health outcomes.
Objective: This scoping review aims to assess the extent and type of evidence available regarding the safety and maternal side effects of the Pfizer RSVpreF vaccine administered during pregnancy.
Methods: A systematic search was conducted across six databases, including Ovid MEDLINE, EMBASE, CINAHL, Cochrane Central, Web of Science, and ClinicalTrials.gov, for peer-reviewed studies published between January 2020 and September 2024. Studies focusing on maternal outcomes following RSVpreF vaccine administration in pregnancy were included. Data extraction and analysis were performed following the JBI methodology for scoping reviews, with results documented in a PRISMA-ScR flow diagram.
Results: Out of 1,259 initially identified studies, five met the inclusion criteria. The studies, spanning 2020–2024, included randomized controlled trials and a retrospective cohort study, primarily regarding high-income populations. Findings indicate that the RSVpreF vaccine is generally well tolerated, with the most common side effects being mild-to-moderate local injection site reactions. Adverse events, including preeclampsia and gestational hypertension, were reported inconsistently across studies. A recent cohort study suggested a possible association between vaccine administration and hypertensive disorders of pregnancy (HDP), though findings remain inconclusive.
Conclusion: The Pfizer RSVpreF vaccine appears to be well tolerated in pregnant women, but gaps in maternal safety data warrant further research. Future studies should prioritize high-risk patients and underrepresented populations, long-term maternal health outcomes, and potential associations with hypertensive disorders to ensure comprehensive vaccine safety and equitable access.
