COVID-19 vaccination and all-cause and non-COVID-19 mortality. A revaluation of a study carried out in an Italian Province.

Publication date: Feb 06, 2024

The COVID-19 vaccination prevents COVID-19 specific mortality. Well planned population-based studies, however, are necessary to evaluate the overall effectiveness of vaccination programmes. A study carried out in the province of Pescara is used 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 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. 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.

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Concepts Keywords
Crude All-cause mortality
Italian Bias
July COVID-19
Vaccinated COVID-19 vaccination status
COVID-19 Vaccines
COVID-19 Vaccines
Humans
Italy
Non COVID-19 mortality
Vaccination

Semantics

Type Source Name
disease MESH COVID-19
disease VO vaccination
disease VO population
disease VO effectiveness
disease VO vaccine
disease VO vaccinated
disease VO unvaccinated
disease MESH death
disease VO time
disease VO vaccinee
drug DRUGBANK Esomeprazole
drug DRUGBANK Eszopiclone
drug DRUGBANK D-Alanine
disease MESH infection
drug DRUGBANK Trestolone
disease VO dose
disease VO vaccine dose
disease VO monthly
drug DRUGBANK Aspartame
disease MESH infarction
disease MESH stroke
disease MESH pericarditis
disease MESH deep venous thrombosis
disease VO Optaflu
disease VO Gap
drug DRUGBANK Coenzyme M
disease IDO process
disease MESH comorbidity
disease VO frequency
disease MESH influenza
disease VO vaccine effectiveness
drug DRUGBANK Cholesterol
disease MESH myocardial infarction
disease MESH COPD

Original Article

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