A Critical Analysis of All-Cause Deaths during COVID-19 Vaccination in an Italian Province

"Abstract: Immortal time bias (ITB) is common in cohort studies and distorts the association estimates between the treated and untreated. We used data from an Italian study on COVID-19 vaccine 
effectiveness, with a large cohort, long follow-up, and adjustment for confounding factors, affected by ITB, with the aim to verify the real impact of the vaccination campaign by comparing the risk of 
all-cause death between the vaccinated population and the unvaccinated population. We aligned all subjects on a single index date and considered the 'all-cause deaths' outcome to compare the survival distributions of the unvaccinated group versus various vaccination statuses. The all-cause death hazard ratios in univariate analysis for vaccinated people with 1, 2, and 3/4 doses versus unvaccinated people were 0.88, 1.23, and 1.21, respectively...

4. Discussion

... For those vaccinated with two doses, the loss of life expectancy (RMTL) in 739 days is 1.37 (CI 95 = 1.27–1.48; p < 0.0001) times that of the unvaccinated. This means that the subjects vaccinated with two doses lost 37% of life expectancy compared to the unvaccinated population during the follow-up considered...

5. Conclusions

... We found all-cause death risks to be even higher for those vaccinated with one and two doses compared to the unvaccinated and that the booster doses were ineffective. We also found a slight but statistically significant loss of life expectancy for those vaccinated with 2 or 3/4 doses."