SARS-CoV-2 infection and COVID-19 vaccination in cancer patients undergoing immune checkpoint inhibitors

Cancer patients are susceptible to severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Different antitumor treatments have attracted wide attention in the context of coronavirus disease 2019 (COVID-19), especially immune checkpoint inhibitors (ICIs) that have revolutionized oncology changes. It may also have protective and therapeutic roles in viral infections. In this article, we collected 26 cases of SARS-CoV-2 infection during ICIs therapy and 13 related to COVID-19 vaccination from Pubmed, EMBASE, and Wed of Science. Of these 26 cases, 19 (73.1%) presented mild cases and 7 (26.9%) were severe cases. Melanoma (47.4%) was a common cancer type in mild cases and lung cancer (71.4%) in severe cases (P = 0.016). The results showed that their clinical outcomes varied widely. Although there are similarities between the immune checkpoint pathway and COVID-19 immunogenicity, ICIs therapy overactivated T cells, which often leads to immune-related adverse events. In fact, the COVID-19 vaccine has been shown to be safe and effective in patients treated with ICIs. In this review, we report the vital clinical observations of SARS-CoV-2 infection or vaccination in cancer patients treated with ICIs and explore the potential interaction between them.