Safety of COVID-19 vaccines in pregnancy: a VAERS based analysis

Purpose: Since vaccination against COVID-19 is recommended in pregnant people, we aimed to provide further evidence on the safety profile of COVID-19 vaccines in pregnancy. Methods: Data on COVID-19 vaccines adverse events following immunizations (AEFIs) in pregnant people were retrieved from the open-access Vaccine Adverse Event Reporting System (VAERS) from December 2020 to April 2022. Results: From December 2020 to April 1, 2022, a total of 4,869 reports involving pregnant women at COVID-19 vaccination were reported to VAERS. Among vaccines recipients, most belonged to the age group between 30 and 39 years old (3,029; 62.21%) and nearly half experienced an adverse event within 48 h of immunization (2,344; 48.14%). Overall, 21,816 suspected adverse reactions associated with COVID-19 vaccines were reported, and for as many as 80.43% of patients, they were described as non-serious. Most reactions occurred after administration of the mRNA-1273 (53.34%) and the BNT162b2 (40.68%) vaccines, while only a small proportion were related to the Johnson & Johnson’s vaccine (5.69%). The most common non-pregnancy specific adverse events were headache (482; 2.21%), fatigue (472; 2.16%), and pyrexia (436; 2.00%), while adverse pregnancy outcomes with the highest reporting rate were abortions spontaneous (762; 3.49%), and vaginal haemorrhage (229; 1.05%). Conclusion: This post-marketing survey on VAERS data have provided updated evidence on the safety of COVID-19 vaccines during pregnancy, thus supporting clinicians in recommending maternal immunization.