Effectiveness and safety of COVID-19 vaccine in pregnant women: A systematic review with meta-analysis

BackgroundThere are limited data regarding COVID-19 vaccination during pregnancy. ObjectivesTo evaluate the effects of COVID-19 vaccination received during pregnancy on SARS-CoV-2 infection, COVID-19-related hospitalisation, COVID-19-related intensive care unit (ICU) admission and maternal-fetal complications. Search strategyMEDLINE, CINHAL, Embase, Scopus and CENTRAL databases, as well as , reference lists, related articles and grey literature sources. Selection criteriaRandomised controlled trials, non-randomised studies of interventions, pregnant women, COVID-19 vaccination during pregnancy. Data collection and analysisStudy selection, risk-of-bias assessment, data extraction and assessment of the certainty of evidence using the GRADE method were performed independently by two authors. Meta-analyses were performed using Cochrane RevMan 5.4. PROSPERO registration number: CRD42022308849. Main resultsWe included 14 observational studies (362 353 women). The administration of a COVID-19 vaccine during pregnancy resulted in a statistically significant reduction in SARS-CoV-2 infection (OR 0.46, 95% CI 0.28-0.76) and COVID-19-related hospitalisation (OR 0.41, 95% CI 0.33-0.51). The effect appeared to be greater in fully vaccinated women, for both infection (OR 0.31, 95% CI 0.16-0.59) and hospitalisation (OR 0.15, 95% CI 0.10-0.21). However, the certainty of evidence was very low. The difference in COVID-19-related ICU admission between vaccinated and unvaccinated individuals did not reach statistical significance (OR 0.58, 95% CI 0.13-2.58). Finally, there were no statistically significant differences in any of the maternal-fetal complications considered in the included studies. ConclusionsCOVID-19 vaccination administered during pregnancy seems to reduce SARS-CoV-2 infection and COVID-19-related hospitalisation, with no significant effects on maternal-fetal complications.