Effectiveness of COVID -19 vaccine on cancer patients in one Latin American country: A follow-up of ACHOC-C19 study.

Abstract

e18721 Background: In our experience during the first year of development of ACHOC-C19 study, we observed 26% mortality in patients with cancer and COVID 19 infection. The impact of vaccination was not evaluated prior to the implementation of this strategy worldwide in this kind of population. It was proposed to evaluate the effectiveness of immunization during the second phase of our investigation. Methods: Cohort study derived from the National Registry of Patients with Cancer and COVID-19 (ACHOCC-19). Data were collected from June 2021 since vaccine was available. Patients were: older than 18 years, diagnosed with cancer (solid tumors), treated and/or under follow-up, and with COVID-19 infection. The comparative analysis of the vaccinated and non-vaccinated cohort is presented. Outcomes included: all-cause mortality within 30 days of infection diagnosis, hospitalization, and mechanical ventilation. Effect estimation was performed through relative risk (RR) and multivariate analysis for each event, using generalized linear models of the binomial family. Results: 896 patients were included, 470 were older than 60 years (52.4%) and 59% women (n = 530). 172 patients were recruited in the vaccinated cohort and 724 in the non-vaccinated cohort (ratio: 1 to 4.2). The cumulative incidence of hospitalization among the unvaccinated was 42.4% (n = 307), and among the vaccinated, 29% (n = 50); invasive mechanical ventilation requirement was 8.4% (n = 61) in unvaccinated, and 4.6% (n = 8) in vaccinated. The cumulative incidence of mortality from all causes in the unvaccinated was 17% (n = 123) and in the vaccinated 4.65% (n = 8). Table summarizes the multivariate analysis. The adjusted RR for mortality for the unvaccinated is 3.4 (95% CI: 1.7-6.8), for hospitalization 1.36 (95% CI: 1.08-1.72), and for mechanical ventilation 2.1 (95% CI: 1.02-4.2). Conclusions: The incidence of complications and death in patients with cancer and COVID-19 infection is significantly higher in those who have not received a vaccination schedule compared to those who have been vaccinated. Immunization should be promoted and intensified in this population group.[Table: see text]