PHILADELPHIA — Six years ago, researchers estimated that 43 million U.S. adults suffered some degree of impairment in their sense of taste or smell. Then came COVID-19, adding untold millions to the total.
Scientists have a good understanding of the biology behind many such cases — though the way in which COVID impairs smell is still not fully understood, and effective treatments are few.
But there is one question on which researchers say they are largely uninformed:
