Simultaneous mRNA COVID-19 and IIV Vaccination in Pregnancy Study

This study is a prospective, randomized clinical trial. During this study, pregnant women will be randomly assigned to receive IIV and mRNA COVID-19 vaccine either simultaneously or sequentially (7-14 days apart). All participants will receive an mRNA COVID-19 vaccine at Visit 1 (Day 1). Solicited local and systemic symptoms of reactogenicity will be assessed on day of visit for Visits 1 and 2 and daily during the 6 days following each visit using either electronic or paper symptoms diaries, depending on study participant preference. Serious adverse events (SAE) and adverse events of special interest (AESI) will be collected throughout the duration of the study. Pregnant women will be followed through delivery with comprehensive obstetric and infant outcomes obtained from medical record review for 90 days post-delivery. Maternal serum samples will be collected for antibody titers relevant to Influenza and COVID-19 prior to vaccination, at Day 29 (both groups), as well as Days 36-43 if in sequential group. When feasible, maternal blood at delivery and cord blood serum will be analyzed for serological analyses of placental influenza and COVID-19 antibody transfer (cord blood: maternal antibody ratio) will be determined.