PROJECT SUMMARY Pregnant persons are at increased risk for severe COVD-19 illness compared to non-pregnant women of reproductive age, experiencing higher rates of admission to intensive care, mechanical ventilation and death. In addition to the direct impacts on the health of pregnant persons, there is growing evidence to suggest COVID-19 adversely impacts fetal and neonatal health. As of May 2021, three vaccines have been issued Emergency Use Approval in the US. However, because pregnant persons were excluded from initial Phase 3 clinical trials, data to confirm the safety and effectiveness of COVID-19 vaccination during pregnancy are lacking. Driven by this limited data, obstetric and public health governing bodies do not currently directly recommend vaccination for pregnant persons. The American College of Obstetricians and Gynecologists and the US Centers for Disease Control and Prevention (CDC) advise that COVID-19 vaccines should not be withheld from pregnant persons. As a result, the decision to vaccinate is made at the individual level, and pregnant persons express anxiety around making this decision. Additional data to inform the safety and effectiveness of COVID-19 vaccines administered during pregnancy would strengthen current clinical guidelines. Despite weak guidance, individuals are choosing to be vaccinated during pregnancy. As of 3 May 2021, 106,241 pregnant persons were reported as having received a COVID-19 vaccine through V-SAFE, the CDC’s active vaccine safety surveillance system. When surveyed, more than 50% of pregnant persons report an intention to receive a COVID-19 vaccine. Phase 2/3 clinical trial data are currently being gathered to evaluate safety and efficacy. While these clinical trial data are being collected, we have the opportunity to learn from large observational studies of pregnant persons who have chosen to be vaccinated. Leveraging existing national medical claims and electronic medical records for more than 870,000 pregnancies, we plan to conduct large-scale post-implementation cohort studies to evaluate the uptake, safety and effectiveness of COVID-19 vaccines administered during pregnancy. Completion of the proposed research will provide important epidemiological evidence on the safety and effectiveness of COVID-19 vaccination during pregnancy. This evidence will aid informed decision and policy-making around COVID-19 vaccination for pregnant persons.

PROJECT NARRATIVE Although pregnant persons are at higher risk of severe COVID-19 infection, there is currently limited data to inform COVID-19 immunization policies for this population group. Drawing from national, linked health information for over 870,000 mother-infant pairs, this research will provide large-scale evidence on the uptake, safety and effectiveness of maternal COVID-19 vaccination in terms of perinatal, neonatal and infant health outcomes. Completion of this research will facilitate informed decision-making among pregnant persons, those planning pregnancy and their healthcare providers.