COVID-19 Vaccination in Cancer Patients Older Than 70 Years Undergoing Active Treatment. Seroconversion Rate and Safety.

Patients with cancer have a high risk of intubation, intensive care unit admission, or death from the coronavirus disease (COVID-19); age and comorbidities are additional risk factors. Vaccination is effective against COVID-19; however, patients with cancer have been excluded from pivotal clinical trials for COVID-19 vaccines. Data on COVID-19 vaccination in cancer patients who are older are lacking. This observational study was conducted to evaluate the seropositivity rate and safety of a two-dose regimen of the BNT162b2 or mRNA1273 vaccine in older patients (age ≥ 70 years) with solid tumors or with hematological malignances who are undergoing active anticancer treatment or whose treatment has been terminated within 6 months of vaccination. The control group was composed of healthy volunteers that were age-matched with the patient group. The primary endpoint was the seropositivity rate, and the secondary endpoints were safety, the factors influencing seroconversion, the IgG titers of patients versus healthy volunteers, and post-vaccine COVID-19 infection between 20 March 2021 and 14 July 2021. At our Institution (Oncology and Hematology Department, Hospital of Piacenza, North Italy), 443 patients with cancer underwent a program for COVID-19 vaccination; 115 (25.95%) were older than 70 (range 71-86 years) and form the basis of this study. All 115 patients accepted the vaccination. There were 64 female patients (55.65%), 94 patients (81.74%) with solid tumors, and 21 patients (18.26%) with hematological malignances. The primary endpoint of seropositivity was observed in 75 patients (65.22%)-70.21% in patients with solid tumors and 42.86% in patients with hematological malignances-versus in 100% of patients in the control group. Of the secondary endpoints, no grade 3-4 side effects and no COVID-19 infections were reported. The factor influencing seroconversion was the type of cancer. The patients' median IgG titers were significantly lower than in the control groups. The COVID-19 vaccines BNT162b2 and mRNA1273 were effective and safe among older patients with cancer when administered in real-world conditions.