Managing Chronic Illnesses During COVID-19, Vaccine Impact

Those managing chronic illnesses such as cancer have been heavily impacted during the COVID-19 pandemic due to their risk factors. While the vaccine supplies some relief, according to University of Arizona Health Sciences researchers, patients undergoing active chemotherapy have a lower immune response to two doses of the COVID-19 vaccine, but a third dose increases the response.

“We wanted to make sure we understand the level of protection the COVID-19 vaccines are offering our cancer patients, especially as restrictions were being eased and more contagious variants were starting to spread,” chief of Gastrointestinal Medical Oncology at the UArizona Cancer Center and director of the Cancer Center Clinical Trials Office, Rachna Shroff, MD, MS, said in a press release.

To gather more information on the cancer patient’s response to the vaccine, Shroff and a research team studied 53 Cancer Center patients’ immunosuppressive active cancer therapy, including chemotherapy. The team compared the immune response of the patients following the first and second dose of the Pfizer-BioNTech COVID-19 vaccine with that of 50 healthy adults.

After two vaccine doses, most cancer patients showed an immune response, indicating they had antibodies for SARS-CoV-2.

“We were pleasantly surprised,” said Deepta Bhattacharya, PhD, professor of immunobiology in the College of Medicine-Tucson and a member of the Cancer Center and BIO5 Institute. “We looked at antibodies, B cells, and T cells, which make up the body’s defense system, and found the vaccine is likely to be at least partially protective for most people on chemotherapy.”

However, the immune response was much lower than in healthy adults, and some of the patients had no response to the vaccine at all. According to researchers, this translated to less protection against COVID-19, especially the Delta variant.

Twenty patients returned to receive a third shot, which boosted the immune response for most. Overall, the group immune response after the third shot reached levels similar to those of individuals who were not on chemotherapy after two doses.

The interdisciplinary research team was formed soon after the Pfizer-BioNTech vaccine was approved in late 2020. The team focused on patients with solid tumors, such as gastrointestinal and breast cancer, and excluded those on immunotherapy.

“The fact that we could answer this question in such a short time speaks to what can happen when you leverage the varied expertise we have within UArizona Health Sciences,” said Shroff, who also is a member of the BIO5 Institute. “Cancer Center clinicians went above and beyond to enroll their patients in the study because we all had a unified goal to protect our patients.”