SARS-CoV-2 vaccination in patients with solid tumors or hematological malignancies: Is the pandemic over for fully vaccinated patients?

Excerpt

Patients with cancer were reported to have an elevated risk of acquiring SARS-CoV‑2 (severe acquired respiratory syndrome coronavirus 2) infection [1], possibly indicating an increased susceptibility to the virus, and have a high risk of developing severe COVID-19 (coronavirus disease 2019), as well as dying from the disease. In a large study from the US [2], hospitalization for COVID-19 was necessary in 47.46% of oncologic patients, who had acquired the disease, and an overall mortality of 14.93% was seen, while numbers for patients without cancer were 24.26% and 5.26%, respectively. A 30-day mortality rate of 30% was found in a meta-analysis of cohort studies for patients with a diagnosis of cancer who were hospitalized for COVID-19 [3]. Available data point to certain subgroups of cancer patients being especially vulnerable, such as patients with hematological malignancies, most notably patients with leukemia and lymphoma being under active treatment, but also patients with lung cancer [4]. Delayed or absent viral clearance has been repeatedly observed in COVID-19 survivors with severe immune suppression [5]. More recently, the persistent immune dysregulation by SARS-CoV‑2 infection in patients with hematological malignancies as compared to patients with solid tumors has been delineated by high throughput, high content flow-cytometry and multiplex cytokine analysis [6]. With regard to risk factors in the population of cancer patients, chemotherapy (i.e., cytostatic agents) was associated with a higher risk of mortality from COVID-19 in some studies [4], but not in others [7]. Concerns were expressed that checkpoint inhibitors may predispose cancer patients to severe COVID-19, due to therapeutically activated T‑cells augmenting the virally induced cytokine storm, but so far these concerns could not be substantiated. As in the general population, mortality of COVID-19 in cancer patients increases substantially with age. Currently, there are insufficient data for estimating COVID-19 risks for cancer survivors, i.e., patients in long-term follow-up without active disease or treatment, but highest risk for severe COVID-19 seems to affect cancer patients with active and/or advanced disease [1]. …