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

In a highly promising find, a study shows that nearly all cancer patients vaccinated against COVID-19 with mRNA vaccines developed strong immune response three to four weeks following their second dose. The results appeared in the journal Cancer Cell.

Researchers assessed a total of 131 patients with a median age of 63.  In the total population, most patients (n=106) had solid cancers compared with (n=25) patients with hematological malignancies. The study population was 80% White, 18% Hispanic, and 2% Black.

According to the results, 94% of cancer patients developed antibodies to COVID. However, seven high-risk patients did not. “We could not find any antibodies against the virus in those patients,” said Dimpy P. Shah, MD, PhD, of the Mays Cancer Center, home to UT Health San Antonio MD Anderson, via a press release. “That has implications for the future. Should we provide a third dose of vaccine after cancer therapy has completed in certain high-risk patients?”

“With other vaccines and infections, patients with cancer have been shown not to develop as robust an immune response as the general population,” said study senior coauthor Ruben Mesa, MD, FACP, executive director of the Mays Cancer Center. “It made sense, therefore, to hypothesize that certain high-risk groups of patients do not have antibody response to COVID-19 vaccine.”

“Patients with hematological malignancies, such as myeloma and Hodgkin lymphoma, were less likely to respond to vaccination than those with solid tumors,” said Pankil K. Shah, MD, PhD, of the Mays Cancer Center, who served as co-lead author of the study with Alfredo Addeo, MD, senior oncologist at the Geneva University Hospital.

In the high-risk groups, patients receiving the monoclonal antibody Rituximab within six months of vaccination developed no antibodies. Also, patients on chemotherapy developed an attenuated antibody response. “How that relates to protection against COVID-19, we don’t know yet,” Dr. Dimpy Shah said.

In regard to such a small percentage of the population being people of color, Dr. Mesa said: “We recommend that future studies be done in Black, Asian and Hispanic patients, as well, to see if there are any differences in vaccination immune response.”

The fast-spreading Delta variant and other mutants of the COVID-19 virus were not examined in the study, the researchers noted. Also, the research team did not analyze the response of infection-fighting T cells and B cells in the patients with cancer. “We recommend that future studies be done in Black, Asian and Hispanic patients, as well, to see if there are any differences in vaccination immune response,” Dr. Mesa said.

In countries where there is lack of vaccination, there is talk that one dose might confer adequate protection, but this may not be true in the case of patients with cancer, Dr. Dimpy Shah said.

“We observed a significant difference in response when two doses were given,” Dr. Shah said. “At least for patients with cancer, two doses are very important for robust antibody response.”


Dr. Pankil Shah also touted the study’s uniqueness, because unlike previous studies that evaluated immune response on the day of the second dose or within seven days of it, this study waited three to four weeks to obtain results.

After post-vaccination, patients with high-risk cancers, especially those receiving anti-CD20 antibodies, should continue to take precautions. “They still need to have that awareness that they could potentially be at risk because their body has not responded to vaccination,” Dr. Pankil Shah said.