SARS-CoV-2 Vaccination in Patients with Cancer and COVID-19 in Mexico

Vaccination is the best preventive measure for SARS-CoV-2 infection; however, efficacy is lower in cancer patients. During the pandemic period, Mexico was characterized by the use of seven different COVID-19 vaccine platforms, and oncologic patients were not prioritized for vaccination. We report the outcomes of COVID-19 in cancer patients after the beginning of the national vaccine campaign in Mexico.

All patients with cancer and COVID-19 diagnosed at Instituto Nacional de Cancerología from 14 February 2021 to 28 February 2022 were included. Primary outcomes were the proportion of individuals who required hospital admission and/or invasive mechanical ventilation, according to the vaccination status; 30-day mortality; the period of infection; and other cancer-related variables.

A total of 691 patients were included; 524 (76%) had solid tumors (STs), and 167 (24%) had hematologic malignancies (HMs). Patients infected in the first two periods, had lower rates of vaccination and higher rates of mortality and hospitalization compared to those infected in the Omicron period. In the multivariate analysis, vaccination status was independently associated with hospitalization in patients with STs (aOR 0.38, 95%CI 0.19-0.75, p = 0.005), but it was not associated with invasive mechanical ventilation and 30-day mortality. In those with HMs, vaccination status was not associated with any outcome; in this group, only recent chemotherapy and time of infection were associated with invasive ventilation.

Vaccination significantly reduced hospital admissions in patients with STs. Infections occurring during the Omicron period were associated with improved outcomes in both ST and HM patients. Despite having a lesser impact in immunosuppressed patients, vaccination is an essential strategy, and access to vaccination campaigns in patients with cancer needs to be prioritized.