Insights on COVID-19 Vaccination for Patients With Cancer
The coronavirus disease 2019 (COVID-19) pandemic has resulted in tremendous pressure and demands on global healthcare systems, bringing some to the brink of collapse. However, the unprecedented speed with which vaccines have been developed, with a few already approved globally and several currently in development, offers hope that the spread of the virus can be controlled, facilitating a return to normality in the not-so-distant future. Cancer patients are at higher risk of severe disease and mortality from COVID-19 than people without cancer. A recent review of fatality rates led to the conclusion that patients with active cancers, especially those with hematologic malignancies and lung cancer, should be considered as a high-priority group for vaccination. This is in line with the vaccine allocation recommendations of the United States Advisory Committee on Immunization Practices (ACIP) within the Centers for Disease Control and Prevention (CDC), which states that patients with cancer should be offered the COVID-19 vaccine during an early phase of the vaccination program.
However, there is a scarcity of data on the safety and, particularly, the efficacy of the COVID-19 vaccines in patients with cancer. An important consideration is that the immunocompromised state of many cancer patients, as a result of their malignancy and/or treatment, may lead to a dampened immune response to the vaccine. Nevertheless, statements from the American Society of Clinical Oncology (ASCO) and the European Society for Medical Oncology (ESMO) support vaccination, including for patients who are undergoing cancer treatments, as long as there are no contraindications to any of the vaccine components. Other considerations include the timing of vaccination in relation to cancer therapy schedules, which may affect the level of immunity achieved, and potential interactions between the vaccine and cancer treatments. For example, in patients who are undergoing chemotherapy, vaccination is recommended before the initiation of chemotherapy, whenever possible. Regarding patients receiving immunotherapy, there are currently no data to suggest that a vaccine will worsen the toxicities of therapy, and therefore, patients should be offered the vaccine at a convenient timepoint. With respect to possible interactions between the vaccine and cancer therapies, the type of vaccine is important, since live attenuated/non-replicating vaccines risk causing vaccine-related infection in patients undergoing immunosuppressive treatment. In contrast, although there are limited data, no specific safety concerns have been raised with mRNA vaccines in cancer patients, including in those patients who are receiving immune checkpoint inhibitors, cytotoxic therapy, or targeted agents. The mRNA-based vaccines use mRNA encapsulated in lipid nanoparticles, which facilitate the transport of mRNA into the cell where protein translation triggers an immune response. Since liposome-based vectors may accumulate in solid tumors by passive targeting, the immunogenicity of the vaccine may be affected, and therefore, dosing could be an important issue to ensure optimal immunity.
ESMO emphasizes the need for a pharmacovigilance plan, and continued research in the context of clinical trials and registries in order to generate more clinical data on vaccine efficacy and safety in cancer patients and to guide decision-making on the choice of vaccine technology. Overall, vaccination is deemed essential in all patients with cancer, despite the possibility of reduced vaccine immunogenicity in patients with active cancer undergoing anticancer treatment. The benefit of vaccination outweighs the increased risk of severe symptoms and mortality due to COVID-19.
References
Ribas A, et al. Cancer Discovery 2021; Jan 18 [Online ahead of print].
Han HJ, et al. International Immunopharmacology 2021; Dec 2 [Online ahead of print].
https://www.esmo.org/covid-19-and-cancer/covid-19-vaccination