“Healthy Vaccine Bias”, that is, what can invalidate the evaluation of the effectiveness of vaccines
Science is not a series of Ipse Dixit, right or wrong, absolute belief versus heresy, but is, or should be, a continuous discussion and verification. Unfortunately this is happening less and less and the academic world and research suffer from it, as recent scandals also demonstrate.
For example, there has always been talk of the exceptional effectiveness of vaccines in reducing mortality, with even peaks of 90% in the prevention of deaths. Yet some doctors have a doubt, and express it through normal academic channels, that is, with a letter to a scientific journal, in this case the New England Journal of Medicine.
Drs Hoeg, Duriseti and Prasag write, referring to Arbel research from December 2021 that showed a vaccine efficacy of 90% in preventing deaths
The lower 90% adjusted mortality due to Covid-19 reported among participants who received a booster cannot, with certainty, be attributed to the booster. The "healthy vaccinated bias" in this population may also have led to overestimation of vaccine efficacy in similar studies by Clalit Health Services. The inclusion of non-COVID-19 related mortality in all observational studies of the Covid-19 vaccine would provide important context.
What does it mean ? That while mortality was calculated on the entire population of unvaccinated people, even extremely sick people who would have died anyway, the vaccine booster was instead given to relatively healthy people, excluding those who had fatal pathologies. This means that if we considered 100 people in the unvaccinated group and 100 in the vaccinated group, there were also seriously ill people in the first group, while in the second group these were excluded. So it stands to reason that there was a skewing in mortality between the two groups, with the former, however, would have shown more deaths anyway, because it included extremely sick people. The exact equality between the treated group and the control group would have been violated. This is a problem that often arises in research related to vaccines, and is due to the fact that seriously ill people are not vaccinated
The dispute is part of the normal scientific process and in fact obtains an answer: the authors of the original study admit that serious hospitalized people with other pathologies have not been inoculated. So the 90% effectiveness in preventing mortality with boosters would be inflated and would need corrections, as the study authors themselves note.
I note that the same journal published original research, scientific dispute, and researcher response. Because this is how science should work, real science, not with bans and jail for protesters. Complaints are answered, if you have something to say.
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The article "Healthy Vaccine Bias", that is, the one that can invalidate the evaluation of the effectiveness of vaccines, comes from Scenari Economici .
This is a machine translation of a post published on Scenari Economici at the URL https://scenarieconomici.it/healthy-vaccine-bias-cioe-quello-che-puo-inficiare-la-valutazione-dellefficacia-dei-vaccini/ on Sun, 06 Aug 2023 13:38:28 +0000.