BACKGROUND: Cancer patients are considered a priority group for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination given their high risk of contracting severe coronavirus disease 2019 (COVID-19). However, limited data exists regarding the efficacy of immunization in this population. In this study we assess the immunologic response after COVID-19 vaccination of cancer versus non-cancer population. METHODS: PubMed, Cochrane Central Register of Controlled Trials (CENTRAL), and Web of Science databases were searched from March 01, 2020, through August 12, 2021. Primary endpoints were anti-SARS-CoV-2 spike protein (S) immunoglobulin G (IgG) seroconversion rates, T-cell response, and documented SARS-CoV-2 infection after COVID-19 immunization. Data was extracted following the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guidelines. Overall effects were pooled using random effects models. RESULTS: This systematic review and meta-analysis included 35 original studies. Overall, 51% (95% confidence interval [CI], 41-62) and 73% (95%CI, 64-81) of cancer patients developed anti-S IgG above the threshold level after partial and complete immunization, respectively. Patients with hematologic malignancies had a significantly lower seroconversion rate than those with solid tumors after complete immunization (65% vs 94%; P<0.0001). Compared to non-cancer controls, oncological patients were less likely to attain seroconversion after incomplete (RR 0.45 [95%CI 0.35-0.58]) and complete (RR 0.69 [95%CI 0.56-0.84]) COVID-19 immunization schemes. Cancer patients had a higher likelihood of having a documented SARS-CoV-2 infection after partial (RR 3.21; 95%CI 0.35-29.04) and complete (RR 2.04; 95%CI 0.38-11.10) immunization. CONCLUSIONS: Cancer patients have an impaired immune response to COVID-19 vaccination compared to controls. Strategies that endorse the completion of vaccination schemes are warranted. Future studies should aim to evaluate different approaches that enhance oncological patients’ immune response.

Fuente: European Journal of Cancer
Available online 26 October 2021