Among 67 patients with hematologic malignancies, or cancers that affect the blood, bone marrow or lymph nodes, 46 percent did not produce antibodies a few weeks after receiving their second dose of COVID-19 vaccine, according to an analysis led by researchers at the University of Pittsburgh School of Medicine and UPMC Hillman Cancer Center.
Among patients with chronic lymphocytic leukemia included in the analysis, just three in 13 produced measurable antibodies in the weeks after being fully vaccinated, according to the findings, which are undergoing peer-review and were published April 7 in the preprint server medRxiv.
Overall, older patients were more likely to have a lower antibody response compared to younger patients.
"As we see more national guidelines allowing for unmasked gatherings among vaccinated individuals, clinicians should counsel their immunocompromised patients about the possibility that COVID-19 vaccines may not fully protect them against SARS-CoV-2," said Ghady Haidar, MD, senior author of the study and transplant infectious diseases expert at UPMC. "Our results show that the odds of the vaccine producing an antibody response in people with hematologic malignancies are the equivalent of a coin flip."
"We're still working to determine why people with hematologic malignancies — particularly those with CLL — have a lower antibody response and if this low response also extends to patients with solid tumors," said Mounzer Agha, MD, the study's lead author and hematologist at UPMC Hillman Cancer Center.