COVID-19 is known to often cause a complete loss of smell (anosmia) or a partial loss of smell (hyposmia), and similar disturbances occur with other types of viral infections, as viruses damage cells and receptors in the nasal cavity. Many people recover their sense of smell completely, but this does not always happen.
Nearly 3,000 people who had recovered from the infection and 569 who reported being free of the disease participated in the study. On average, recovered participants were tested 671 days after their first positive test for SARS-CoV-2.
The results showed that approximately 80% of those who complained of smell problems actually had impaired smell. However, signs of loss or deterioration of their sense of smell were detected in 66% of those who were unaware of their impaired sense of smell. The rate of impaired smell was also high among people without confirmed COVID-19, reaching 60%, which could indicate hidden or asymptomatic infections.
It is noteworthy that the virus damages cells and receptors in the nose, leading to a decrease or loss of the sense of smell. The sense of smell usually recovers partially or incompletely in many people.
Scientists hypothesize that damage to the central nervous system following infection may reduce conscious perception of smells, potentially leading to the problem going unnoticed. If this data reflects the general situation, millions of people could be living with an unnoticeable loss of their sense of smell.
The article was published in JAMA Network Open.
