(261) Real-World Safety of The Pfizer-BioNTech COVID-19 Vaccine in Pregnancy: Data from The Organization of Teratology Information Specialists (OTIS) Pregnancy Registry

Sunday, August 28, 2022

8:00 AM – 1:45 PM CEST

Location: Hall C

Publication Number: 1306

Presenting Author(s)

Christina D. Chambers, PhD
– Professor, University of California, San Diego, UCSD, La Jolla, California, United States

Co-Author(s)

Kenneth L. Jones
– University of California San Diego, San Diego, CA, United States
Diana Johnson
– UC San Diego, Department of Pediatrics, San Diego, CA, United States
Michael Schatz
– Kaiser Permanente, San Diego, CA, United States

Background: Data indicate that pregnant women infected with COVID-19 are more likely to develop severe illness and are at increased risk of pregnancy complications. As of February 7, 2022, >198,000 participants in the U.S. Centers for Disease Control and Prevention’s V-Safe program were pregnant when they received a COVID-19 vaccination. Information on the real-world safety of COVID-19 vaccination in pregnancy is essential.

Objectives: The objectives of this study are to assess risks of major congenital malformations, spontaneous abortion, elective termination, stillbirth, preterm delivery, small for gestational age infants at birth, or infants who were small for age at one year in pregnancies/infants prenatally exposed to the Pfizer-BioNTech COVID-19 vaccine compared to pregnant women who received no COVID-19 vaccine in pregnancy.

Methods: This study involves secondary analysis of data from the Organization of Teratology Information Specialists (OTIS) Pregnancy Registry as part of the Vaccines and Medications in Pregnancy Surveillance System (VAMPSS). The OTIS Registry enrolls pregnant women residing in the U.S. or Canada and captures data on exposures, outcomes and covariates through maternal interviews and abstraction of obstetric, hospital and pediatric records through one year of age. The study population for this analysis includes Registry participants who met eligibility criteria on or after December 11, 2020, the date the U.S. Food and Drug Administration granted emergency-use authorization for the Pfizer-BioNTech vaccine. The target sample size is 1,100 pregnant women who received any dose of the Pfizer-BioNTech vaccine from 30 days prior to the last menstrual period through the end of pregnancy, and 900 comparison women who received no COVID-19 vaccine in pregnancy. Analyses will focus on exposure to any dose, total number of doses, and specific dose(s) (1st, 2nd, 3rd or booster) of the vaccine received in the relevant gestational window for each specific outcome.

Results: As of October 1, 2021, 921 participants in the OTIS Pregnancy Registry were eligible for inclusion in the Pfizer-BioNTech COVID-19 vaccine exposure cohort (83.7% of the target sample); 427 participants met eligibility criteria for the comparator cohort (47.4% of the target sample). The distribution of the earliest COVID-19 vaccine dose by gestational timing and total number of doses in pregnancy is described in the Table. Enrollment is planned for completion in 2022; final results will be available in 2025.

Conclusions: It is possible to address real-world safety of a novel vaccine using an existing pregnancy registry to identify exposed and comparator pregnancies immediately following authorization of the vaccine.