By American College of Physicians
December 20, 2021
A target trial emulation research study found that in a senior population of U.S. veterans with high comorbidity problem, mRNA vaccine efficacy at avoiding infection with COVID-19 was substantially lower than previously reported but effectiveness versus death was extremely high. These finding recommend that complementary infection mitigation efforts remain crucial for pandemic control, even with vaccination. The research study is published in Annals of Internal Medicine.
The real-world effectiveness of the Moderna or Pfizer-BioNTech COVID-19 mRNA vaccines in ethnically and racially varied populations across the entire United States is not well characterized, specifically in more susceptible populations, such as elderly persons with high comorbidity burden. The U.S. Department of Veterans Affairs (VA) health care system is the biggest national, comprehensive healthcare system in the United States. As such, it uses the opportunity to assess vaccines in this population.
Of the more than 5 million individuals receiving care in the Veterans Affairs health care system, those who received at least 1 dosage of the Moderna or Pfizer– BioNTech COVID-19 vaccine from 11 December 2020 to 25 March 2021 (n = 2,099,871) were matched to unvaccinated controls in a 1:1 ratio according to market, scientific, and geographic attributes. The researchers found that vaccine efficiency at 7 or more days after the 2nd vaccine dose was 69% for SARS-CoV-2 infection and 86% for SARS-CoV-2– related death during follow-up extending to 30 June 2021. Vaccine efficiency did not decrease when follow-up was extended from 31 March to 30 June 2021.
Recommendation: 20 December 2021, Annals of Internal Medicine.DOI: 10.7326/ M21-3256.
