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Coronaviruses

Comparative Effectiveness of COVID-19 Vaccines Against the Delta Variant

Strategic Insights

— 1 min read

Researchers at the University of Michigan published a study comparing the effectiveness of three COVID-19 vaccines - Pfizer-BioNTech, Moderna, and Johnson & Johnson-Janssen - in preventing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and COVID-19 hospitalization during the pre- and post-Delta variant period. The study found that mRNA-based vaccines were more effective against hospitalization and infection compared to the Johnson & Johnson-Janssen vaccine.

Key Takeaways:

  • The study compared the effectiveness of three COVID-19 vaccines - Pfizer-BioNTech, Moderna, and Johnson & Johnson-Janssen - in a large cohort of vaccinated and unvaccinated patients in the Michigan Medicine healthcare system.
  • The researchers assessed vaccine effectiveness using two analyses: an inverse propensity weighted (IPW) Kaplan-Meier (KM) analysis based on time from vaccination, and a Cox model based on calendar time with vaccination as a time-varying covariate.
  • The study found that recipients of the mRNA-1273 vaccine had a lower risk of SARS-CoV-2 infection compared to Ad26.COV2.S recipients (HR = 0.60; 95% CI: [.43-.83]; P = .003) and BNT162b2 recipients (HR = 0.64; 95% CI: [.54-.76]; P = .02).
  • The researchers concluded that the effectiveness of mRNA-based vaccines against Delta hospitalization is substantially greater than the effectiveness of the Ad26.COV2.S (Johnson & Johnson-Janssen) vaccine.
  • The study received financial support from the NIH National Institute of Allergy & Infectious Diseases (NIAID).

Statistics:

  • Hazard ratio (HR) = 0.37 (95% CI: [.14-.98]; P = .05) for BNT162b2 recipients.
  • Hazard ratio (HR) = 0.21 (95% CI: [.07-.64]; P = .006) for mRNA-1273 recipients.
  • Hazard ratio (HR) = 0.60 (95% CI: [.43-.83]; P = .003) for mRNA-1273 recipients compared to Ad26.COV2.S recipients.
  • Hazard ratio (HR) = 0.64 (95% CI: [.54-.76]; P = .02) for mRNA-1273 recipients compared to BNT162b2 recipients.

Sources:

  • Zhao, L., et al. (2022). Comparative Effectiveness of Coronavirus Disease 2019 (Covid-19) Vaccines Against the Delta Variant. Clinical Infectious Diseases, 2022.
  • University of Michigan, Dept. of Biostatistics, Ann Arbor, MI 48109, United States.
  • National Institute of Allergy & Infectious Diseases (NIAID).

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