COVID-19 Vaccination Leaves Cancer Patients Unprotected

A study published by researchers at Mayo Clinic Cancer Center on December 12, 2021, found that cancer patients who receive chemotherapy ― and some targeted therapies, such as CDK4/6 inhibitors and therapies targeted at B cells, may mount an inadequate immune response to COVID-19 vaccination.

"It is important for patients with cancer who are receiving chemotherapy to receive a COVID-19 vaccine," commented Saranya Chumsri, M.D., a Mayo Clinic hematologist and oncologist, and author of the paper, in a press statement issued on January 20, 2022.

Dr. Chumsri says this advice also applies to patients with cancer taking CDK 4/6 inhibitors.

These inhibitors are a newer class of medicines used to treat hormone-receptor-positive and HER2-negative breast cancers. 

Dr. Chumsri says that while CDK 4/6 inhibitors are not conventionally considered to be as immunosuppressive as chemotherapy, her research on patients with breast cancer who take these drugs found that they exhibited less optimal neutralizing antibody activity.

Dr. Chumsri recommends that antibody levels be tested in these patients after vaccination, and they should consider receiving booster vaccinations for COVID-19.

Dr. Chumsri anticipates having additional data later in 2022 regarding broader immune responses to COVID-19 vaccinations, including cellular and antibody responses in patients receiving chemotherapy and targeted therapies with booster vaccinations.

Separately, the U.S. CDC says 'If you have a moderately or severely weakened immune system or are being treated for cancer, the CDC recommends that you get one more vaccine dose at least 28 days after receiving a two-shot mRNA vaccine. Additional doses are given to improve response to the initial vaccine series in people with weakened immune systems.'

The Mayo Clinic Cancer Center is designated as a comprehensive cancer center by the National Cancer Institute.