New research shows that Multiple Sclerosis (MS) patients undergoing anti-CD20 (aCD20) treatment—which depletes the B cells that contribute to the MS attacks—are able to mount robust T-cell responses to the mRNA COVID-19 vaccines, despite having a muted antibody response to the vaccines.

Because B cells are responsible for antibody production, patients’ ability to produce antibodies that prevent the virus from entering and infecting a person’s cells is significantly muted when the B cells are depleted with aCD20 treatment. But the same patients are nonetheless able to mount very good responses of the second protective arm of their immune system, which uses T cells to eliminate cells once infected (thereby preventing viral spread to other cells), according to new research from the Perelman School of Medicine in a new paper published in Nature Medicine.

“The message from this study is clear—it is worthwhile for patients with MS receiving aCD20 treatment to get a COVID-19 vaccine, which will prevent severe illness,” says one of the senior authors, E. John Wherry, chair of Systems Pharmacology and Translational Therapeutics and director of the Penn Institute for Immunology. “Based on this body of evidence, we urge patients with MS receiving aCD20 treatment to get a COVID-19 vaccine if they haven’t already.”

—Kelsey Odorczyk