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Journal Article Research Support, Non-U.S. Gov't Ppublish 6 citations

PubMed: 36071540 DOI: 10.1093/cid/ciac739

Pregnancy Status at the Time of Coronavirus Disease 2019 Vaccination and Incidence of Severe Acute Respiratory Syndrome Coronavirus 2 Infection.

Clin Infect Dis 76(1):57-65

Authors: Maria C Magnus, Siri E Håberg, Ellen Ø Carlsen, Jeffrey C Kwong, Sarah A Buchan, Deshayne B Fell

Affiliations

  • Centre for Fertility and Health, Norwegian Institute of Public Health, Oslo, Norway.
  • Public Health Ontario, Toronto, Canada.
  • ICES, Toronto, Canada.
  • Dalla Lana School of Public Health, University of Toronto, Toronto, Canada.
  • Centre for Vaccine Preventable Diseases, University of Toronto, Toronto, Canada.
  • Department of Family and Community Medicine, University of Toronto, Toronto, Canada.
  • University Health Network, Toronto, Canada.
  • School of Epidemiology and Public Health, University of Ottawa, Ottawa, Canada.
  • Children's Hospital of Eastern Ontario Research Institute, Ottawa, Canada.

Abstract

BACKGROUND

Pregnant women are recommended to receive coronavirus disease 2019 (COVID-19) vaccines; however, relative effectiveness of vaccination by pregnancy status is unclear.

METHODS

We compared the relative effectiveness of messenger RNA (mRNA) COVID-19 vaccines according to whether women received both doses while pregnant (n = 7412), 1 dose while pregnant (n = 3538), both doses while postpartum (n = 1856), or both doses while neither pregnant nor postpartum (n = 6687). We estimated risk of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection starting 14 days after the second dose using Cox regression, reporting hazard ratios (HRs) and 95% confidence intervals (CIs). Second, we examined relative effectiveness of a third (booster) dose while pregnant compared to outside pregnancy. The major circulating variant during the study period was the Delta variant.

RESULTS

Fifty-four percent of women received 2 doses of the BNT162b2 vaccine, 16% received 2 doses of the mRNA-1273 vaccine, while 30% received 1 dose of both vaccines. Compared to women who received both doses while neither pregnant nor postpartum, the adjusted HR for a positive SARS-CoV-2 polymerase chain reaction test was similar if the woman received both doses while pregnant (1.04 [95% CI, .94-1.17]), 1 dose while pregnant and 1 dose before or after pregnancy (1.03 [95% CI, .93-1.14]), or both doses while postpartum (0.99 [95% CI, .92-1.07]). The findings were similar for BNT162b2 (Pfizer-BioNTech Comirnaty) and mRNA-1273 (Moderna Spikevax), and during Delta- and Omicron-dominant periods. We observed no differences in the relative effectiveness of the booster dose according to pregnancy status.

CONCLUSIONS

We observed similar effectiveness of mRNA vaccines against SARS-CoV-2 infection among women regardless of pregnancy status at the time of vaccination.

MeSH

Coronavirus, Pregnancy, Sars-Cov-2, Vaccines, Incidence, Severe Acute Respiratory Syndrome, Rna, Messenger, Vaccination, Covid-19, Communicable Diseases, Postpartum Period, Infections, Rna

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