COVID-19 vaccination, all-cause mortality, and hospitalization for cancer: 30-month cohort study in an Italian province

Abstract

Anecdotal reports suggested an association between SARS-CoV-2 vaccination and some cancers, but no formal assessment has been published. This population-wide cohort analysis was aimed at evaluating the risk of all-cause death and cancer hospitalization by SARS-CoV-2 immunization status. Using National Health System official data, the entire population of the Pescara province, Italy was followed from June 2021 (six months after the first vaccination) to December 2023. Cox models were adjusted for age, gender, previous SARS-CoV-2 infection, and selected comorbidities. Of the 296,015 residents aged ≥11 years, 16.6% were unvaccinated, 83.3% received ≥1 dose, and 62.2% ≥3 doses. Compared with the unvaccinated, those receiving ≥1 dose showed a significantly lower likelihood of all-cause death, and a slightly higher likelihood of hospitalization for cancer (HR: 1.23; 95% CI: 1.11-1.37). The latter association was significant only among the subjects with no previous SARS-CoV-2 infection, and was reversed when the minimum time between vaccination and cancer hospitalization was set to 12 months. The subjects who received SARS-CoV-2 vaccination showed a substantial reduction in all-cause mortality, and a risk of cancer hospitalization that varied by infection status, cancer site, and the minimum lag-time after vaccination. Given that it was not possible to quantify the potential impact of the healthy vaccinee bias and unmeasured confounders, these findings are inevitably preliminary. See also the graphical abstract(Fig. 1).

Keywords: COVID-19; SARS-CoV-2; all-cause mortality; cancer hospitalization; vaccines.

Table 1. Characteristics of the sample, overall and by COVID-19 vaccine status.

Table 2. Main outcomes, overall and by COVID-19 vaccine status.

Table 3. Adjusted hazards ratios (95% confidence interval ‒ CI) ^A of all-cause death, all cancers, and selected cancers. The unvaccinated group is the reference category for all analyses.

Figure 1. Graphical abstract

Figure 2. Adjusted hazards ratios (HR) and 95% confidence intervals (CI) ^A of hospitalization for all cancers and selected cancers, by exposure to ≥ 1 or ≥ 3 vaccine doses ^B and by lag-time. The unvaccinated group is the reference category for all analyses.

^A Based on Cox proportional hazards models, adjusted for gender, age, diabetes, hypertension, cardiovascular or cerebrovascular disease, chronic obstructive pulmonary disease, kidney disease, and infection status. ^B When comparing the unvaccinated versus the subjects who received at least one dose, the follow-up started on March 30, 2021 for the unvaccinated individuals, and after the selected lag-times from the first dose for the vaccinated subjects. When comparing the unvaccinated versus the subjects who received at least three doses, the follow-up started on September 28, 2021 for the unvaccinated, and after the selected lag-times from the third dose for the vaccinated subjects.