How a Highly Effective Vaccine Turns Into a Mediocre Vaccine — or Worse
The implication of the “healthy vaccinee” phenomenon — when estimating vaccine effectiveness — is called confounding bias. A naïve comparison of Covid mortality in vaccinated people and unvaccinated people, even if age-adjusted, is grossly misleading because the latter have higher risk of death to begin with. At least part of their higher Covid mortality, if not all, has nothing to do with not being vaccinated. They are simply sicker people.
How a Highly Effective Vaccine Turns Into a Mediocre Vaccine — or Worse Read Journal Article