Covid‐19 vaccines in cancer patients. Seropositivity and safety. systematic review and meta‐analysis

Patients with cancer are among the most vulnerable groups of the COVID‐19 pandemic, whereas vaccinations can represent a cornerstone in overcoming the pandemic itself. However, cancer patients were excluded from clinical trials for COVID‐19 vaccinations, and thus the data on the immunogenicity and safety of COVID‐19 vaccines in cancer patients are limited. In this systematic review, we assessed the seroconversion rate and the safety of COVID‐19 vaccinations in cancer patients. We searched a bibliographic database up until 31 July 2021. Utilizing inclusion criteria, six studies were selected and analyzed for this meta‐analysis. This included 621 cancer patients and 256 controls. Results show that patients with solid tumors show adequate antibody responses (>90%), though the antibody titers were significantly lower than those of healthy controls. Similarly, a significantly lower rate of seroconversion was registered in patients with hematologic malignances. The vaccines showed a good safety profile; no grade 3–4 adverse events were regis-tered. This review demonstrates generally high immunogenicity from COVID‐19 vaccines in patients with cancer, with better results for solid tumors than hematological malignances, and with a good safety profile.