Thousands of people say they’ve developed tinnitus after they were vaccinated against Covid. While there is no proof yet that the vaccines caused the condition, theories for a possible link have surfaced among researchers.

Shaowen Bao, an associate professor in the physiology department of the College of Medicine at the University of Arizona, Tucson, believes that ongoing inflammation, especially in the brain or spinal cord, may be to blame.

Bao, a longtime tinnitus sufferer and a representative of the American Tinnitus Association’s scientific advisory board, has studied tinniuts for more than a decade.