BACKGROUND AND PURPOSE:

• Magnus et al. (JAMA, 2022) examined the risk of adverse pregnancy outcomes after vaccination against SARS-CoV-2 during pregnancy

METHODS:

• Registry-based retrospective cohort study
  • Norway and Sweden
  • January 2021 through January 2022
• Population
  • Singleton pregnancies
  • Delivery after ≥22 weeks
• Exposures
  • Vaccination: Pfizer | Moderna | AstraZeneca
• Study design
  • Risk of primary outcomes were evaluated using Cox regression models
  • Vaccination served as a time-dependent exposure variable
  • Risk of secondary outcomes were evaluated using logistic regression
  • Random-effects meta-analysis was used to combine results between countries
• Primary outcomes
  • Preterm birth and stillbirth
• Secondary outcomes
  • Small for gestational age
  • Low Apgar score
  • Neonatal care admission

RESULTS:

• 157,521 pregnancies
  • Mean maternal age at delivery: 31 years
  • Vaccinated against COVID-19 while pregnant: 18%
    • Pfizer: 12.9%
    • Moderna: 4.8%
    • AstraZeneca: 0.3%
  • Vaccinated during
    • First trimester: 0.7%
    • Second trimester: 8.3%
    • Third trimester: 9.1%
• Vaccination against SARS-CoV-2 was not significantly associated with increased risk of
  • Preterm birth
    • Vaccinated: 6.2 per 10,000 pregnancy days
    • Non-vaccinated: 4.9
    • Adjusted hazard ratio (aHR) 0.98 (95% CI, 0.91 to 1.05)
  • Stillbirth
    • Vaccinated: 2.1 per 10,000 pregnancy days
    • Non-vaccinated: 2.4
    • aHR 0.86 (95% CI, 0.63 to 1.17)
  • Small for gestational age
    • Vaccinated: 7.8%
    • Non-vaccinated: 8.5%
    • Difference –0.6% (95% CI, –1.3 to 0.2)
    • Adjusted OR (aOR) 0.97 (95% CI, 0.90 to 1.04)
  • Low Apgar score
    • Vaccinated: 1.5%
    • Non-vaccinated: 1.6%
    • Difference –0.05% (95% CI, –0.3 to 0.1)
    • AOR 0.97 (95% CI, 0.87 to 1.08)
  • Neonatal care admission
    • Vaccinated: 8.5%
    • Non-vaccinated: 8.5%
    • Difference 0.003% (95% CI, –0.9 to 0.9)
    • AOR 0.97 (95% CI, 0.86 to 1.10)

CONCLUSION:

• COVID-19 vaccination during pregnancy was not associated with an increased risk of adverse pregnancy outcomes
• Most of the vaccinations in this population occurred during the second and third trimester
• The authors state

COVID-19 in pregnancy is also associated with adverse pregnancy outcomes affecting the child, and vaccination reduces the risk of COVID-19 during pregnancy

An added benefit of vaccination of individuals against SARS-CoV-2 during pregnancy is that antibodies are transferred to the fetus, which offers infants protection against the virus during the first months of life

This is particularly beneficial because none of the existing vaccines are currently approved for use in children younger than 2 years

Learn More – Primary Sources:

Association of SARS-CoV-2 Vaccination During Pregnancy With Pregnancy Outcomes

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