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

Background There are limited data regarding COVID-19 vaccination during pregnancy. Objectives To 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 strategy MEDLINE, CINHAL, Embase, Scopus and CENTRAL databases, as well as ClinicalTrials.gov, reference lists, related articles and grey literature sources. Selection criteria Randomised controlled trials, non-randomised studies of interventions, pregnant women, COVID-19 vaccination during pregnancy. Data collection and analysis Study 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 results We 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. Conclusions COVID-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.