COVID-19 vaccination during pregnancy could prevent approximately 2,500 infant hospitalizations and 450 maternal hospitalizations annually at full coverage, according to a modeling study using US surveillance data from January 2024 to May 2025.
Researchers from Stanford University, University of Washington, and Baylor College of Medicine developed a decision-analytic model using COVID-19–Associated Hospitalization Surveillance Network (COVID-NET) data. The model estimated hospitalizations under scenarios without vaccination compared with three coverage levels: 15%, 50%, and 100% of pregnant patients receiving vaccination during the second or third trimester.
Without vaccination, more than 7,000 infant hospitalizations and over 3,000 hospitalizations among pregnant patients were expected. At 50% vaccination coverage, an estimated 1,251 infant hospitalizations and 228 maternal hospitalizations could be averted. Even at 15% coverage—reflecting recent uptake rates—vaccination was projected to prevent 375 infant hospitalizations and 68 maternal hospitalizations.
Infants younger than 6 months are ineligible for COVID-19 vaccination. Maternal vaccination during pregnancy transfers antibodies to newborns, providing passive immunity for approximately 6 months. Pregnancy also doubles the risk of severe COVID-19.
The model used vaccine effectiveness estimates of 35% against infant hospitalization and 33% against maternal hospitalization. These estimates were derived from recent observational studies of primarily annual COVID-19 vaccination during pregnancy.
"This study demonstrates meaningful benefit of COVID-19 vaccination during pregnancy, which has moderately waned over time, but still supports the need to reconsider the decision to remove vaccine eligibility during pregnancy,” wrote lead author Nathan C. Lo, MD, PhD, of the Division of Infectious Diseases and Geographic Medicine, Stanford University.
In May 2025, the US Department of Health and Human Services issued guidance to remove pregnancy as an indication for COVID-19 vaccination.
Limitations of the study findings depended on recent patterns of incidence and severity, which may change as viral variants and immunity evolve. Vaccine effectiveness estimates were drawn from observational studies and may be subject to bias. Uptake of COVID-19 vaccination during pregnancy has historically been low, which could reduce real-world benefits. Outcomes were sensitive to assumptions about incidence, severity, and vaccine effectiveness.
The study was conducted by researchers from Stanford University, the University of Washington, and Baylor College of Medicine. Several authors reported conflicts of interest, which were disclosed in the publication.
Source: JAMA Pediatrics