COVID-19 Vaccination in Patients With Cancer and Patients Receiving HSCT or CAR-T Therapy: Immune Response, Real-World Effectiveness, and Implications for the Future

Abstract

Patients with cancer demonstrate an increased vulnerability for infection and severe disease by SARS-CoV-2, the causative agent of COVID-19. Risk factors for severe COVID-19 include comorbidities, uncontrolled disease, and current line of treatment. Although COVID-19 vaccines have afforded some level of protection against infection and severe disease among patients with solid tumors and hematologic malignancies, decreased immunogenicity and real-world effectiveness have been observed among this population compared with healthy individuals. Characterizing and understanding the immune response to increasing doses or differing schedules of COVID-19 vaccines among patients with cancer is important to inform clinical and public health practices. In this article, we review SARS-CoV-2 susceptibility and immune responses to COVID-19 vaccination in patients with solid tumors, hematologic malignancies, and those receiving hematopoietic stem cell transplant or chimeric-antigen receptor T-cell therapy.

Keywords: chimeric-antigen receptor T-cell therapy; hematologic malignancies; hematopoietic stem cell transplant; mRNA COVID-19 vaccines; solid tumors.

Figure 1.

Summary of the range of pooled antibody response rates after 2 doses of COVID-19 vaccines across hematologic malignancies [38–40]. Seroresponse rates will vary depending on other factors including disease treatment status, type of therapy, and timing of vaccination. Red represents the lowest seroresponse rate observed and blue represents the highest seroresponse rate observed. ANHL, aggressive non-Hodgkin lymphoma; CLL, chronic lymphocytic leukemia; HL, Hodgkin lymphoma; INHL, indolent non-Hodgkin lymphoma; MM, multiple myeloma; MPN, myeloproliferative neoplasms.

Figure 2.

Summary of the range of pooled antibody response rates after 2 doses of COVID-19 vaccines in patients who received hematopoietic stem cell transplant (HSCT) or chimeric antigen receptor T-cell therapy (CAR-T) [16, 52–54]. Seroresponse rates will vary depending on other factors including disease treatment status, type of therapy, and timing of vaccination. Red represents the lowest seroresponse rate observed and blue represents the highest seroresponse rate observed. alloHSCT, allogeneic HSCT; autoHSCT, autologous HSCT.