Study finds cancer patients with poor antibody response to COVID-19 vaccines lack secondary immune response

Patients with the blood cancer multiple myeloma often mount a poor antibody response to novel coronavirus (COVID-19) vaccines. Mount Sinai researchers have discovered that these patients also have a weak response from a different part of the immune system, known as T cells, according to a research letter published in the journal Cancer Cell.

In a trial of 44 patients with multiple myeloma, those with low or no antibody response to the COVID-19 mRNA also had few or no T cells that could have protected them from a severe COVID-19 infection. T cells are an important component of the immune system and play a central role in the body’s ability to fight off infections, and researchers said they had believed they might respond even in people with a poor antibody response.

The study analyzed patients with multiple myeloma and compare their T cell responses to COVID-19 proteins to those in a control group of healthy people. Approximately 96 percent of patients with detectable antibodies against the “spike” protein—an important component of SARS-CoV-2, the virus that causes COVID-19, and a frequent target of vaccines—had detectable COVID-19-specific T cell responses; in contrast, only 35 percent of the patients who had no detectable antibodies had a T cell response. Fewer patients on certain multiple myeloma therapies that impact the immune system had a T cell response compared to those on other therapies, according to the study.

The researchers said they continue to study the durability of antibody and T cell responses of these patients after COVID-19 mRNA vaccines and boosters. These findings show that with the current rapid spread of more transmissible viral variants, such as the Delta variant, patients with immune system disorders, including multiple myeloma, should work with their doctors and understand their risk and response to the COVID-19 vaccines. Researchers believe this study underscores high-risk patients’ need for booster vaccination and continued safety precautions such as masking and social distancing.