Immunogenicity of SARS-CoV-2 mRNA Vaccines in Patients with Cancer: Findings from an International Collaborative Cohort Study

Abstract

Patients with cancer experience higher burden of SARS-CoV-2 infection, disease severity, complications, and mortality, compared to the general population. SARS-CoV-2 mRNA vaccines have shown to be highly effective in clinical trials; however, few data are available on the e cacy of SARS-CoV-2 vaccines in patients with cancer. Using a prospective cohort study design, we assessed the seroconversion rates and anti-SARS-CoV-2 S antibody titers following the 1st and 2nd dose of BNT162b2 and mRNA-1273 SARS-CoV-2 vaccines in patients with cancer at centers in U.S. and Europe from January 2021 to April 2021. Among 131 patients included in the immunogenicity analysis, most (94%) developed antibody levels; however, 6% showed no seroconversion after completing the mRNA vaccination series. No differences in seroconversion rates were observed between BNT162b2 and mRNA-1273 vaccine groups. Patients with solid tumors (98%) were much more likely to seroconvert and develop higher antibody titers than those with hematological malignancy (77%). Although seroconversion rates were consistently high in patients receiving different types of anti-cancer therapy except anti-CD-20 antibody; the antibody titers were much lower in patients who received cytotoxic chemotherapy, immunotherapy, or monoclonal antibody compared to those on clinical surveillance or receiving endocrine therapy within six months prior to vaccination. None of the patients on anti-CD-20 antibody therapy developed an antibody response, even after receiving 2 doses of the vaccines. After correlating with cell-mediated immunity in a subset of patients at high-risk for antibody non-response, we propose exploring the addition of a second booster, or convalescent plasma therapy, or postpone vaccination until after completion of their speci c anti-cancer treatment. Although encouraging results, we suggest high-risk vaccinated patients with cancer to continue taking safety precautions until their immune response is con rmed at 4 weeks after 2nd dose of mRNA vaccines. We also highly encourage all eligible individuals in the general population to get vaccinated to ensure the protection of the most vulnerable groups, such as those with cancer.