Antibody Response to SARS–CoV-2 mRNA-1273 Vaccination in Patients With Cancer: Single-Institution Study

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In a single-institution study reported in JAMA Oncology, Giuliano et al found that seroconversion after two doses of the SARS–CoV-2 mRNA-1273 (Moderna) vaccine in patients with cancer was lower among patients with hematologic malignancies vs solid tumors and differed according to cancer treatment received.

The study included 515 patients sequentially enrolled from patients presenting for mRNA-1273 vaccination at Moffitt Cancer Center between January 12 and 25, 2021. Of these, 301 had a hematologic malignancy and 214 had solid tumors.

Key Findings

Among all patients, seroconversion occurred in 71.3% (95% confidence interval [CI] = 67.1%–75.1%) after the first dose and in 90.3% (95% CI = 87.4%–92.7%) after the second dose.

Seroconversion after the second dose was higher among patients with solid tumors (98.1%, 95% CI = 95.3%–99.5%) than among those with a hematologic malignancy (84.7%, 95% CI = 80.1%–88.6%). Among those with hematologic malignancies, the seroconversion rate was lowest among patients with lymphoid cancer (70.0%, 95% CI = 60.5%–78.4%), particularly among those with chronic lymphocytic leukemia (65.2%) and B-cell non-Hodgkin lymphoma (58.2%).

Seroconversion rates were 6.3% (95% CI = 0.2%–30.2%) among patients vaccinated within 6 months after anti-CD20 monoclonal antibody treatment, 53.3% (95% CI = 26.6%–78.7%) among those treated 6 to 24 months before vaccination, and 94.2% (95% CI = 91.7%–96.1%) among those not receiving anti-CD20 treatment.

Higher antibody levels were observed among 18 vaccinated adults without cancer participating in a separate community study (geometric mean [GM] = 7303.7 arbitrary units [AU]/mL), compared with patients in the current study with solid tumors (GM = 1754.6 AU/mL) or hematologic malignancy (GM = 745.6 AU/mL).

Factors associated with low antibody levels after vaccination included receipt of anti-CD20 treatment within 6 months before vaccination (GM = 15.5 AU/mL), treatment with small-molecule agents (GM = 646.7 AU/mL), low lymphocyte counts (GM = 547.4 AU/mL) and low IgG levels (GM = 494.7 AU/mL).

The investigators concluded, “This cohort study found that the mRNA-1273 SARS–CoV-2 vaccine induced variable antibody responses that differed by cancer diagnosis and treatment received. These findings suggest that patients with hematologic cancer and those who are receiving immunosuppressive treatments may need additional vaccination doses.”

Anna R. Giuliano, PhD, of the Moffitt Cancer Center, is the corresponding author for the JAMA Oncology article.

Disclosure: The study was supported by a grant from the National Cancer Institute. For full disclosures of the study authors, visit