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Vaccination has become crucial to preventing COVID infection or significantly reducing the risk of hospitalization if illness develops. Since the vaccine became available in late 2020, it has been strongly recommended for immunocompromised patients. However, the research that went into developing the vaccine didn’t look at whether it would work for the severely immunocompromised, such as cancer patients who have weakened immune systems due to treatment.

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.

Headshot of Dr. Jeffrey Lancet

Dr. Jeffrey Lancet, Chair, Malignant Hematology Department

“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.”

The observational study included 46 patients, 30 with AML and 16 with MDS. Most of the patients had completed treatment, with only a third (15 patients) on active therapy at the time of vaccination. After the first dose of the vaccine, 69.6% of patients were seropositive, meaning their immune system had developed antibodies to fight the COVID virus. That number rose to 95.7% after the second dose.

“Our results showed antibody titers dramatically increased after the second vaccine dose, indicating a third dose could make a big impact for patients who didn’t respond as well to the initial doses,” said Dr. Akriti Jain, a fellow in the Malignant Hematology Department at Moffitt.

Moffitt has launched a companion study looking at the impact of a third COVID vaccine dose in cancer patients. But as more news comes out about the new omicron variant of the COVID virus, Lancet and Jain stress the importance of vaccination for everyone, not just cancer patients.

“The vaccine has made a huge difference in outcomes and survival. The cancer population stands to benefit because they are already in a heavily vulnerable state. The more people we can get vaccinated with cancer and blood diseases, I think that everyone will get through the next wave,” said Lancet.