94% of Cancer Patients Respond Well to COVID-19 Vaccines

The USA and Swiss-based study found that nearly all patients with cancer developed a good immune response to the experimental COVID-19 mRNA vaccines three to four weeks after receiving their second vaccine dose and reported a study published by the journal Cell on June 18, 2021.

But the fact that a small group of the patients exhibited no response raised questions about how their protection against the virus will be addressed moving forward. Among the 131 patients studied, 94% developed antibodies to the coronavirus. Seven high-risk patients did not.

"We could not find any antibodies against the virus in those patients," said Dimpy P. Shah, M.D., Ph.D., of the Mays Cancer Center, home to UT Health San Antonio MD Anderson, in a press release issued on June 30, 2021.

Seroconversion rates and antibody titers in patients with hematological malignancy were significantly lower than those with solid tumors. In addition, none of the patients with a history of anti-CD-20 antibody in the 6 months before vaccination developed antibody response.

Antibody titers were highest for clinical surveillance or endocrine therapy groups and lowest for cytotoxic chemotherapy or monoclonal antibody groups. Patients on chemotherapy that is toxic to cells developed antibody response, but it was muted compared to the general population.

“How that relates to protection against COVID-19, we don’t know yet,” Dr. Dimpy Shah said. "That has implications for the future. For example, should we provide a third dose of vaccine after cancer therapy has completed in certain high-risk patients?"

The Delta variant and other SARS-CoV-2 coronavirus mutant viruses were not examined in the study. The team also did not analyze the response of infection-fighting T cells and B cells in patients with cancer.