Monovalent COVID-19 booster vaccinations given early in pregnancy and not associated with miscarriage

HealthPartners researchers published new data in JAMA Network is open that shows monovalent COVID-19 booster vaccines given in early pregnancy (before 20 weeks of gestation) were not associated with miscarriage. The research adds to the growing understanding about the safety of booster vaccines for COVID-19 among pregnant women.

The researchers analyzed data from more than 100,000 pregnancies between six and 19 gestational weeks from eight large health systems participating in the analysis of vaccine safety data (VSD). Data was collected between November 1, 2021, and June 12, 2022. Using a window of 28 or 42 days, the researchers found that receiving the booster vaccination was not associated with miscarriage.

Having COVID during pregnancy increases the risk of poor outcomes, yet many women who are pregnant or considering pregnancy are hesitant to get a booster dose due to safety questions. Our data support the safety of booster vaccination in early pregnancy.”

Elise Karpanda, MD, MPH, senior investigator at HealthPartners and lead author of the study

More safety data to support vaccination against COVID-19

Separate research recently published in Obstetrics and gynecology – led by HealthPartners – showed that a booster vaccination for COVID-19 at any time during pregnancy was not associated with an increased risk of serious acute adverse events.

In that study, researchers evaluated data from more than 80,000 pregnancies that occurred between September 23, 2021, and June 30, 2022. A booster vaccination during pregnancy did not increase the risk of thrombocytopenia, myocarditis, venous thromboembolism, ischemic stroke, or Other serious adverse events within 21 or 42 days after vaccination.

We continue to find that COVID-19 vaccines are safe during pregnancy. Continuous vaccine monitoring work is important because it provides reassurance and helps people feel confident about immunizations.”

Malini DeSilva, MD, MPH, researcher at HealthPartners Institute and lead author of the study

Data for both studies came from HealthPartners and seven other large health systems that make up the Vaccine Safety Datalink (VSD). VSD is a research network funded by the Centers for Disease Control and Prevention that conducts post-marketing surveillance of vaccines licensed and in use in the United States. Both studies evaluated the safety of the monovalent COVID-19 booster vaccine. Future studies will evaluate the safety of the bivalent booster.