International Inter-Society Consensus on Vaccination in Pregnancy: Routine and Risk-Based Immunization for Viral and Bacterial Infections

ABSTRACT Vaccination during pregnancy has shifted from simply a maternal protective strategy to one of the most important strategies in protecting both the pregnant individual and the infant in the first weeks of life. Despite this paradigm shift, vaccination recommendations remain fragmented by pathogen, gestational age, and professional organization, often absent a unifying clinical framework. Systematic Review in Accordance with PRISMA 2020 Guidelines: Current Evidence for Maternal Immunization and Alignment of Inter-Society Recommendations With Available Data A systematic search across major bibliographic databases, guideline repositories and reference lists yielded studies that addressed the safety, immunogenicity, effectiveness and implementation of vaccines. Eligible study types were randomized trials, observational cohorts, surveillance reports and systematic reviews. Two Reviewers independently screened records, extracted relevant data and performed risk-of-bias assessment according to each study design. Qualitative synthesis of evidence was conducted and categorized by pathogen, gestational timing, baseline risk, and outcome domain. Fifty-eight studies met our inclusion criteria. For frequently recommended insurances— in particular, influenza, tetanus–diphtheria–acellular pertussis, and COVID-19 —data consistently show maternal safety and substantial reductions in infant morbidity especially when vaccine timing aligns with peak transplacental antibody transfer. Maternal vaccination for respiratory syncytial virus has demonstrated moderate to large reductions in infant hospitalization, though the certainty of this evidence is still evolving. For example, risk-based approaches (e.g., hepatitis B vaccination and rabies post-exposure prophylaxis) demonstrate protective benefits in high-risk contexts with strong evidence largely derived from observational data. There is strong consensus around established vaccines across many guidelines, but newer or context-specific interventions highlight some significant evidence–policy gaps. In summary, maternal immunization should be considered as a risk-stratified intervention that intertwines biological timing with clinical vulnerability and health-system context to guide individualized evidence-based care.