Researchers have published a study in the journal PLOS Medicine suggesting that loss of taste and smell could be indicative of COVID-19 infection. The authors of the study found that coronavirus patients could experience loss of taste and smell and not experience any of the major symptoms such as fever and cough.
At the peak of the COVID-19 crisis in May, the researchers examined 590 people who lost their sense of taste or smell the month before. They also administered coronavirus tests on 567 of these people and found they had the antibodies for COVID-19 – meaning that they may have been infected with the disease without any knowledge of it – except for the loss of smell and taste.
Meanwhile, people usually become contagious within two days of contracting COVID-19.
Out of the 567 (78%) who tested positive for COVID-19 antibodies, about 40% did not experience any cough or fever during their illness. The researchers went on to discover that people who only suffered a loss of smell were three times more likely to have coronavirus antibodies, and those who suffered both losses of smell and taste were four times more likely to have coronavirus antibodies.
The study was conducted by Rachel Batterham, a professor at the University College London, and her colleagues. She said when she started the research in May, some of her colleagues had lost their sense of smell and she suspected it must have been due to some coronavirus infection. Since people were usually tested for COVID-19 when they had serious fever and cough, she was surprised that most of her population samples were positive for coronavirus without getting sick at all.
“At this time, loss of smell was not recognized as a symptom of COVID-19,” she said. “However, I was aware of colleagues who had developed sudden onset loss of smell, so we were convinced that this was a key symptom.”
It must however be pointed out that while the loss of smell usually occurs as a result of allergies, common cold, and upper respiratory infections, COVID-19 can cause inflammation and swelling in the nasal cavity which can be strong enough to block out the ability to smell things, said an assistant professor of laryngology at Rutgers University, Rachel Kaye.
Several findings have established that between 15-68% of coronavirus patients experience loss of smell and taste, and Amesh A. Adalja of the Johns Hopkins Center for Health Security stated that loss of smell and taste appears to be a significant symptom of COVID-19.
“I do think most people don’t necessarily recognize it as a symptom of infection,” Dr. Adalja said. “They may just think it’s odd and not related. But it seems to be a good indicator of COVID-19.”