Publication date: 17/03/2023 – E&P Code: repo.epiprev.it/2772
Authors: Franco Berrino1, Alberto Donzelli2, Paolo Bellavite3, Giovanni Malatesta4
Abstract: The anti-COVID-19 vaccination prevents COVID-19 specific mortality. Well planned population based studies, however, are necessary to evaluate the overall effectiveness of vaccination programs. We profit of a study with this aim, carried out in the province of Pescara, to illustrate the potential biases that may affect such studies. The Pescara study analysed total and non-COVID-19 mortality, and the occurrence of Potentially Vaccine-Related Serious Adverse Events (PVR-SAEs), in vaccinated and unvaccinated people, from January 2021, when vaccines became available, to July 2022. The study reported a markedly lower probability of both total and non-COVID-19 death in vaccinated people. However, the Authors did not include in the denominator of the unvaccinated cohort the population experience of the vaccinated cohort before vaccination (immortal time bias). Correcting the denominator of the unvaccinated cohort, the crude death rate of vaccinated and unvaccinated persons becomes the same. For the same reason, the unvaccinated non-COVID-19 mortality was overestimated, as was the mortality of people receiving only one or two vaccine doses. The confounding by indication and the healthy vaccinee bias will also be discussed, as well as the bias deriving by not considering the evolution of risk over time.
Cite as: Elenco autori, et. al. (2023). COVID-19 vaccination and all-cause and non-COVID-19 mortality. A revaluation of a study carried out in an Italian Province. E&P Repository https://repo.epiprev.it/2772
AVVERTENZA. GLI ARTICOLI PRESENTI NEL REPOSITORY NON SONO SOTTOPOSTI A PEER REVIEW.
1 M.D., past Director Department of Predictive and Preventive Medicine, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
2 M.D., Specialist in Hygiene and Preventive Medicine, independent Medical-Scientific Commission; President of Foundation “Allineare Sanità e Salute”, Milan, Italy
3 M.D., past Professor of Pathology, Department of Medicine, Verona Medical School, Verona, Italy
4 Physics Graduate, Scientific Committee Foundation “Allineare Sanità e Salute”, Pistoia, Italy
Authors’ contributions: Conceptualization, F.B., A.D. and G.M.; methodology, F.B., A.D. and G.M.; validation, F.B., A.D., P.B. and G.M.; formal analysis, F.B., A.D. and G.M.; resources, P.B., A.D. and G.M.; data curation, F.B., A.D. and G.M.; writing—original draft preparation F.B., A.D. and G.M.; writing—review and editing, F.B., A.D., P.B. and G.M.; supervision, F.B., A.D., P.B. and G.M. All authors have read and agreed to the published version of the manuscript.
Competing interests: The authors declare no conflict of interests
Funding disclosure: This research received no external funding
Ethics committee approval: The study was based on publicly available aggregate data. No Ethics committee approval was necessary.
Copyright: Il detentore del copyright è l’autore/finanziatore, che ha concesso a “E&P Repository” una licenza per rendere pubblico questo preprint. The copyright holder for this preprint is the author/funder, who has granted E&P Repository a license to display the preprint in perpetuity.
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