Clinical Perspectives

Understanding the Effects of the COVID Vaccine on Cancer Patients

December 16, 2021


To help better understand the effects of the COVID vaccine on cancer patients, Moffitt Cancer Center launched a study following patients before and after their first and second doses of the Moderna vaccine. Results from a portion of that study are being presented at the American Society of Hematology Annual Meeting. The data focuses specifically on how blood cancer patients with myeloid malignancies, such as acute myeloid leukemia and myelodysplastic syndromes, responded to COVID vaccination.

Patients with myeloid malignancies, including acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS), are at a high risk of severe SARS-CoV-2 infection. It is uncertain whether patients with AML and MDS, who frequently have quantitative or qualitative deficiencies of neutrophils and/or lymphocytes, will develop protective immunity from SARS-CoV-2 vaccines. The primary aim of this analysis was to describe the immune response and safety profile to the mRNA-1273 vaccine amongst a cohort of patients with AML and MDS.

"There’s been a lot of attention given to lymphoid malignancy patients because many of them are on therapies that suppress the immune system. And data shows lower vaccine efficacy rates among that group," said Dr. Jeffrey Lancet, principal investigator of the study and chair of the Malignant Hematology Department at Moffitt. "What we didn’t know is whether patients with myeloid malignancies would mount a response to the vaccine. This patient population can get quite ill and have low white blood cell counts."

Dr. Jeffrey Lancet
Dr. Jeffrey Lancet, Chair, Malignant Hematology Department

In this observational study, the largest reported to date amongst AML and MDS patients with serial serologic data following 2 vaccine doses, we found that the vast majority of patients with AML and MDS converted to seropositivity after two doses of the vaccine. Although the overall sample size was relatively small, most clinical and laboratory variables (including neutropenia and lymphopenia) did not affect the seropositivity rate. Antibody titer levels increased dramatically following the 2nd vaccine dose, indicating the potential utility for serial vaccination (i.e. additional dosing) in poorly-responsive patients. While these findings should be substantiated in a larger cohort, mRNA-273 SARS-CoV-2 vaccine appears to induce a strong humoral response in this population of patients with AML and MDS.

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