The dose- and time-dependent effectiveness and safety associated with COVID-19 vaccination during pregnancy: a systematic review and meta-analysis

Abstract

Objectives: This study aimed to provide guidance for clinical treatment and increase public confidence in COVID-19 vaccines. Methods: The Cochrane Library, Embase, PubMed, Web of Science, ClinicalKey, and other COVID-19 datasets were searched from December 2019 to May 2022. Case-control studies and prospective cohort studies of COVID-19 vaccine effectiveness and safety in pregnant women were included. Results: From day 11 to day 13, after the first dose of the COVID-19 messenger RNA vaccine, the effectiveness was 54% (95% confidence interval: 0.33-0.69). On days 14 to 27, the effectiveness was 59%. There was a 14% increase in vaccine effectiveness 28 days after the first dose was given. The inactivated vaccines showed similar effectiveness. The proportions of placental abruptions, postpartum hemorrhages, miscarriages, stillbirths, premature births, and small for gestational age infants were not significantly different between vaccinated and nonvaccinated pregnant women. Fatigue and fever were also not associated with pregnancy. Conclusion: Our findings affirm that the effectiveness varies for different types of vaccines and is significantly and positively correlated with time in the pregnant population. COVID-19 vaccines have also been deemed safe for pregnant women. Thus, we developed a comprehensive understanding of the role of vaccines in pregnant women.

Keywords

• COVID-19
• Vaccine
• Effectiveness
• Safety
• Obstetrics