One of COVID-19’s many mysteries may finally be solved.
Researchers at Harvard Medical School say they’ve discovered why some people infected with the coronavirus lose their sense of smell.
The symptom, called “anosmia” by doctors, is one of the earliest and most commonly reported indicators of the virus.
Some studies suggest it could actually be a better way to predict whether has the disease than other well-known symptoms like fever and cough.
But, until now, scientists had been baffled by exactly how some patients were being robbed of their senses.
The researchers set out to better understand how smell is altered in coronavirus patients by pinpointing the cell types most vulnerable to SARS-CoV-2, the virus that causes COVID-19.
Through their analysis of various datasets, they found that it attacks cells that support the olfactory sensory neurons, which detect and transmit the sense of smell to the brain.
“Our findings indicate that the novel coronavirus changes the sense of smell in patients not by directly infecting neurons but by affecting the function of supporting cells,” said Sandeep Robert Datta, a neurobiology professor at Harvard Medical School and co-author on the paper.
That means the virus is unlikely to cause permanent damage to olfactory neural circuits, meaning patients can recover their sense of smell, the scientists said.
“I think it’s good news, because once the infection clears, olfactory neurons don’t appear to need to be replaced or rebuilt from scratch,” Datta said in a statement.
But, he added, “we need more data and a better understanding of the underlying mechanisms to confirm this conclusion.”
Their study was published Friday in the peer-reviewed journal “Science Advances.”