Project 467054

The impacts of coronavirus disease 2019 (COVID-19) have been felt everywhere. COVID-19, which was declared a global pandemic in March 2020, can affect any individual, and pregnant women are particularly more vulnerable to severe infection due to changes in their immune system. COVID-19 vaccination has, therefore, been recommended during pregnancy to prevent adverse maternal and fetal outcomes. However, pregnant people remain hesitant to receive the vaccine, mainly due to safety concerns for their newborns. There is insufficient evidence to describe the impact of COVID-19 vaccination on pregnancy outcomes. From previous research on influenza vaccination during pregnancy, we know that specific scientific approaches are required to perform these studies properly and generate valid results, especially for preterm birth and small-for-gestational-age (SGA) birth, which are very important adverse pregnancy outcomes. Our study will examine preterm and SGA birth following COVID-19 vaccination during pregnancy, while accounting for important scientific challenges, such as differences in characteristics of people who do and do not become vaccinated during pregnancy, as well as very different timing of pregnancy with respect to eligibility/opportunity to become vaccinated given the dramatic changes in the roll-out of the COVID-19 vaccination program in Ontario, to provide a more accurate and comprehensive understanding of the optimal scientific considerations for studies on safety of COVID-19 vaccines in pregnancy. Our findings will inform other scientists, as well as evidence users to ensure that studies of COVID-19 vaccination during pregnancy are using the optimal scientific approach for generating accurate results that can ultimately inform policy makers and pregnant people.