BMJ Public Health (Mar 2024)

Evaluating COVID-19 vaccine effectiveness during pre-Delta, Delta and Omicron dominant periods among pregnant people in the U.S.: Retrospective cohort analysis from a nationally sampled cohort in National COVID Collaborative Cohort (N3C)

  • Nasia Safdar,
  • Harold Lehmann,
  • Jing Sun,
  • Brijesh Patel,
  • Hongfang Liu,
  • Peter Robinson,
  • Elaine Hill,
  • Justin Guinney,
  • Joel Gagnier,
  • Cavin Ward-Caviness,
  • Noha Sharafeldin,
  • Justin Starren,
  • Amit Saha,
  • Lesley Cottrell,
  • Melissa A Haendel,
  • Vignesh Subbian,
  • Kristin Kostka,
  • Farrukh M Koraishy,
  • Andrew E Williams,
  • Robert Hurley,
  • Steve Johnson,
  • Usman Sheikh,
  • Rishi Kamaleswaran,
  • Christopher Dillon,
  • Rena C Patel,
  • Michele Morris,
  • Randeep Jawa,
  • Hemalkumar Mehta,
  • Benjamin Bates,
  • Tellen D Bennett,
  • Nabeel Qureshi,
  • Qiuyuan Qin,
  • Kenneth Wilkins,
  • Sara E Jones,
  • Katie Rebecca Bradwell,
  • Lauren Chan,
  • Jerrod Anzalone,
  • Qulu Zheng,
  • Michael Liebman,
  • Federico Mariona,
  • Emily A Groene Faherty,
  • Anup P Challa,
  • Adam B Wilcox,
  • Adam M Lee,
  • Alexis Graves,
  • Alfred Anzalone,
  • Amin Manna,
  • Amy Olex,
  • Andrea Zhou,
  • Andrew Southerland,
  • Andrew T Girvin,
  • Anita Walden,
  • Anjali A Sharathkumar,
  • Benjamin Amor,
  • Brian Hendricks,
  • Caleb Alexander,
  • Caroline Signore,
  • Carolyn Bramante,
  • Charisse Madlock-Brown,
  • Christine Suver,
  • Christopher Chute,
  • Chunlei Wu,
  • Clare Schmitt,
  • Cliff Takemoto,
  • Dan Housman,
  • Davera Gabriel,
  • David A Eichmann,
  • Diego Mazzotti,
  • Eilis Boudreau Don Brown,
  • Elizabeth Zampino,
  • Emily Carlson Marti,
  • Emily R Pfaff,
  • Evan French,
  • Fred Prior,
  • George Sokos,
  • Greg Martin,
  • Heidi Spratt,
  • Hythem Sidky,
  • JW Awori Hayanga,
  • Jami Pincavitch,
  • Jaylyn Clark,
  • Jeremy Richard Harper,
  • Jessica Islam,
  • Jin Ge,
  • Joel H Saltz,
  • Joel Saltz,
  • Johanna Loomba,
  • John Buse,
  • Jomol Mathew,
  • Joni L Rutter,
  • Julie A McMurry,
  • Karen Crowley,
  • Kellie M Walters,
  • Ken Wilkins,
  • Kenneth R Gersing,
  • Kenrick Dwain Cato,
  • Kimberly Murray,
  • Lavance Northington,
  • Lee Allan Pyles,
  • Leonie Misquitta,
  • Lili Portilla,
  • Mariam Deacy,
  • Mark M Bissell,
  • Marshall Clark,
  • Mary Emmett,
  • Mary Morrison Saltz,
  • Matvey B Palchuk,
  • Meredith Adams,
  • Meredith Temple-O'Connor,
  • Michael G Kurilla,
  • Nicole Garbarini,
  • Ofer Sadan,
  • Patricia A Francis,
  • Penny Wung Burgoon,
  • Philip RO Payne,
  • Rafael Fuentes,
  • Rebecca Erwin-Cohen,
  • Richard A Moffitt,
  • Richard L Zhu,
  • Robert T Miller,
  • Saiju Pyarajan,
  • Sam G Michael,
  • Samuel Bozzette,
  • Sandeep Mallipattu,
  • Satyanarayana Vedula,
  • Scott Chapman,
  • T Shawn,
  • Soko Setoguchi O'Neil,
  • Stephanie S Hong,
  • Tiffany Callahan,
  • Umit Topaloglu,
  • Valery Gordon,
  • Warren A Kibbe,
  • Wenndy Hernandez,
  • Will Beasley,
  • Will Cooper,
  • William Hillegass,
  • Xiaohan Tanner Zhang

DOI
https://doi.org/10.1136/bmjph-2023-000770
Journal volume & issue
Vol. 2, no. 1

Abstract

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Objectives To evaluate the effectiveness of COVID-19 vaccinations (initial and booster) during pre-Delta, Delta and Omicron dominant periods among pregnant people via (1) COVID-19 incident and severe infections among pregnant people who were vaccinated versus unvaccinated and (2) post-COVID-19 vaccination breakthrough infections and severe infections among vaccinated females who were pregnant versus non-pregnant.Design Retrospective cohort study using nationally sampled electronic health records data from the National COVID Cohort Collaborative, 10 December 2020 –7 June 2022.Participants Cohort 1 included pregnant people (15–55 years) and cohort 2 included vaccinated females of reproductive age (15–55 years).Exposures (1) COVID-19 vaccination and (2) pregnancy.Main outcome measures Adjusted HRs (aHRs) for COVID-19 incident or breakthrough infections and severe infections (ie, COVID-19 infections with related hospitalisations).Results In cohort 1, 301 107 pregnant people were included. Compared with unvaccinated pregnant people, the aHRs for pregnant people with initial vaccinations during pregnancy of incident COVID-19 were 0.77 (95% CI 0.62 to 0.96) and 0.88 (95% CI 0.73 to 1.07) and aHRs of severe COVID-19 infections were 0.65 (95% CI 0.47 to 0.90) and 0.79 (95% CI 0.51 to 1.21) during the Delta and Omicron periods, respectively. Compared with pregnant people with full initial vaccinations, the aHR of incident COVID-19 for pregnant people with booster vaccinations was 0.64 (95% CI 0.58 to 0.71) during the Omicron period. In cohort 2, 934 337 vaccinated people were included. Compared with vaccinated non-pregnant females, the aHRs of severe COVID-19 infections for people with initial vaccinations during pregnancy was 2.71 (95% CI 1.31 to 5.60) during the Omicron periods.Conclusions Pregnant people with initial and booster vaccinations during pregnancy had a lower risk of incident and severe COVID-19 infections compared with unvaccinated pregnant people across the pandemic stages. However, vaccinated pregnant people still had a higher risk of severe infections compared with non-pregnant females.