Short-term Reactions Among Pregnant and Lactating Individuals in the First Wave of the COVID-19 Vaccine Rollout
Authors: Alisa Kachikis, Janet A. Englund, Michael Singleton, Isabela Covelli, Alison L. Drake, Linda O. Eckert
Journal: JAMA Network Open (2021)

Vaccines against SARS-CoV-2 are highly effective in preventing COVID-19 illness. 1,2Research has found that COVID-19 is associated with adverse events in pregnancy, 3 and recommendations therefore include offering SARS-CoV-2 vaccines to pregnant and lactating individuals, despite their lack of inclusion in initial clinical trials. 4,5To date, limited data on vaccine and pregnancy outcomes exist for SARS-CoV-2 vaccines in pregnancy and lactation. 6The objective of this study was to investigate experiences of pregnant and lactating individuals after receiving COVID-19 vaccines. MethodsIn January 2021, we launched an online prospective cohort study of adults primarily located in the United States who were pregnant, lactating, or planning pregnancy at the time of COVID-19 vaccination.This study was determined to be exempt from institutional review board review by the University of Washington (UW) Human Subjects Division (Common Rule category 2).We followed the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) reporting guideline.Individuals who were recruited and enrolled online in the UW COVID-19 Vaccine in Pregnancy and Lactation Registry using chain-referral and snowball sampling were invited to participate.Electronic written informed consent was obtained, and self-reported demographic (including race and ethnicity), pregnancy, vaccination perception, and outcome data, including report of day 1 vaccine reactions, were entered via surveys into Research Electronic Data Capture (REDCap) software version 11.1.22021 (Vanderbilt University).Race and ethnicity data were collected to report diversity representation within our study population.Options for race and ethnicity were outlined following the Centers for Disease Control and Prevention's National Health Interview Survey race and ethnicity categories.We performed statistical analysis (ie, χ 2 tests and 1-way analysis of variance, odds ratios [ORs], and 95% CIs) using Stata statistical software version 16.1 (StataCorp).An α level of P Յ .05,2-sided, denoted significance.Data were analyzed from January through March 2021. Results As ofMarch 16, 2021, 17 525 individuals (17 364 [99.7%] women among 17 418 individuals with sex data; mean [SD] age, 33.6 [3.6] years among 17 518 individuals with age data; 15 361 White individuals [87.6%] among all individuals) with known pregnancy status receiving at least 1 dose of a COVID-19 vaccine had enrolled in the study.Owing to missing data, percentages for participant characteristics are among those with data for that variable.There were 3 distinct groups: 7809 individuals who were pregnant (44.6%), 6815 individuals who were lactating (38.7%), and 2901 individuals who were neither pregnant nor lactating but planning pregnancy in the near future (16.5%) at the time of their first vaccine dose.Most individuals received the Pfizer-BioNTech BNT162b2 vaccine (10 790 of 17 431 individuals [61.9%] with data on vaccine type) or Moderna mRNA-1273 vaccine (6592 individuals [37.8%]).Most participants resided in the United States, were employed in health care,