The loss of smell is one of the most common symptoms of COVID-19.
How the virus affects each person’s body determines how long their sense of smell is lost. In many cases, patients continue with their loss of smell even after the virus has left their body. Many patients have reported still experiencing their loss of smell, in some cases up to 16 months after they’ve recovered from COVID-19.
According to Duke University sinus surgeon and researcher, Brad Goldstein, inflammation from fighting the virus causes people to lose their sense of smell.
Goldstein conducted a small study with 24 patients, some of whom still had a loss of smell and others who didn’t.
They started the experiment by taking the nose tissue of nine patients that lost their smell due to COVID-19 and never got it back even long after recovering. Researchers also took samples from healthy patients; two patients had recovered from COVID-19 and didn’t suffer from any long-term loss of smell.
After comparing samples from both groups, they found more T-cells in the infected patients. T-cells are part of the immune system; specifically, they are a type of white blood cell that fights infections. When infected with a virus, the human body produces more T-cells. However, when too many T-cells are produced, this produces interferon-gamma, a substance connected to inflammation. In this case, too much interferon-gamma in the nose interferes with the neurons that allow for a sense of smell. Eventually, the interferon-gamma kills neurons by cutting off their support cells.
Even though researchers don’t have a solution currently, this is a start toward a cure for the loss of smell.
“If we don’t know what’s broken, it’s hard to tell how to fix it,” Goldstein said.
[Source: The Wall Street Journal; Washington Post]