The impacts of the COVID-19 pandemic continue to be felt across the world, but some consequences are more noticeable than others. New research suggests that millions of people may have lost their sense of smell after contracting the virus, without even realizing it.
Contracting COVID-19 can lead to olfactory blindness – anosmia – or a partial loss of smell – hyposmia.
This happens with many viral infections, as viruses interfere with various cells and receptors in the nasal passages. The sense of smell usually returns… but not always.
In a new study, recently published in , scientists wanted to take a closer look at the long-term consequences of COVID-19 on our olfactory abilities.
As Science Alert details, they carried out smell tests on 2,956 volunteers with a history of COVID-19 infections and 569 who had not contracted the virus. On average, smell tests occurred 671 days after participants were initially tested for COVID-19.
Of the group with COVID-19, 1,393 thought they had problems with their sense of smell, and tests confirmed that around 80% of them did, in fact, have these changes.
Surprisingly, the other 163 in this group did not report any smell problems, but the results showed that 66% had hyposmia or anosmia after COVID-19 infections.
“Our findings confirm that those with a history of COVID-19 may be especially at risk of having a weakened sense of smell — a problem that is already little recognized among the general population,” Dr. Leora HorwitzNew York University Grossman School of Medicine.
Among those who had no history of COVID-19, 60% had deficiencies in their sense of smell, which is strangely high. Researchers suggest that some of these people may have had an infection without knowing it.
Extrapolations are never exact, but if the patterns observed in the thousands of people studied are consistent across the world’s population, we could be facing millions of people with hyposmia without knowing.
“Our findings corroborate previous survey-based studies that suggest that SARS-CoV-2 is associated with persistent olfactory dysfunction, and confirm previous small objective studies that show that patients underestimate the loss of smell”, the researchers write in the article.
