Elisabeth McClymont, PhD, discusses reduced severe disease risk from prenatal COVID-19 vaccination

In this interview with Contemporary OB/GYN, Elisabeth McClymont, PhD, assistant professor at The University of British Columbia, discussed findings from a study evaluating the impact of COVID-19 vaccination during pregnancy on severe maternal disease and preterm birth. The results demonstrate clear and clinically meaningful benefits of vaccination for both pregnant individuals and their infants.

According to McClymont, the study showed that COVID-19 vaccination was associated with a substantial reduction in severe maternal illness. Vaccinated pregnant individuals experienced a 62% lower risk of hospitalization for severe COVID-19 compared with their unvaccinated counterparts. Even more striking, the risk of admission to the intensive care unit was reduced by approximately 90%. These findings highlight the strong protective effect of vaccination against the most serious outcomes of COVID-19 in pregnancy.

Beyond maternal benefits, the study also identified significant improvements in neonatal outcomes. Vaccination was associated with a 20% to 36% reduction in the risk of subsequent preterm birth. Given that preterm birth can have lasting consequences for infant health and development, this finding underscores the broader implications of maternal vaccination, extending protection beyond the pregnant individual to the infant.

McClymont emphasized the importance of these results in the context of circulating viral variants. Unlike earlier studies that primarily reflected the Delta period, this analysis included data from both Delta and Omicron variant waves. Because Omicron variants continue to circulate globally, the findings remain highly relevant to current clinical practice. The data demonstrate that vaccination before or during pregnancy continues to offer meaningful protection against severe disease and pregnancy complications.

From a policy perspective, McClymont noted that the strength of these findings should help inform and reinforce clinical guidelines supporting COVID-19 vaccination in pregnancy. In Canada, for example, current recommendations continue to strongly endorse vaccination for pregnant populations, and these results provide additional evidence to sustain and support those policies.

In closing, McClymont broadened the discussion to maternal vaccination more generally. She highlighted the importance of vaccination during pregnancy not only for COVID-19, but also for influenza, Tdap, and RSV. Maternal vaccination allows antibodies to be transferred through the placenta, offering infants protection during the critical early months of life when they are most vulnerable to severe infections. Together, these findings reinforce maternal immunization as a powerful and effective strategy to protect both pregnant individuals and their infants.

No relevant disclosures.

Reference

McClymont E, Blitz S, Forward L, et al. The role of vaccination in maternal and perinatal outcomes associated with COVID-19 in pregnancy. JAMA. 2025. doi:10.1001/jama.2025.21001