Haywire immune response in the nose that lingers after infection could cause smell loss, study finds The nose knows why some people still can’t smell long after recovering from Covid-19.
A haywire immune response in the olfactory system was found to explain why some people still can’t smell long after symptoms of the disease have abated, according to a small, peer-reviewed study published Wednesday in the journal Science Translational Medicine.
In some cases, the immune or inflammatory response was detected in patients with smell loss up to 16 months after recovery from Covid-19.
Compared with people who can smell normally, patients with long-term smell loss had fewer olfactory sensory neurons, cells in the nose responsible for detecting smells and sending that information to the brain.