Loss of smell and taste are a strong sign that someone is infected with Covid-19, according to new research published Thursday.
People who lose either smell or taste should consider self-isolating, even if they have no other symptoms, researchers in Britain said.
“Our findings show that loss of smell and taste is a highly reliable indicator that someone is likely to have Covid-19 and if we are to reduce the spread of this pandemic, it should now be considered by governments globally as a criterion for self-isolation, testing and contact tracing,” Rachel Batterham of University College London and University College London Hospitals, who helped lead the study team, said.
How the study was conducted: The team studied 590 volunteers who experienced a new loss of smell or taste. They tested 567 of them for coronavirus.
Of the 567, 77.6% tested positive for SARS-CoV-2 antibodies. In total, 80.4% of participants reporting smell loss and 77.8% of those reporting taste loss had a positive test result, the team reported in the journal PLoS Medicine.
Nearly 40% of those who tested positive for antibodies had neither a fever nor a cough.
Batterham and her colleagues also found that participants with a loss of smell alone were nearly three times more likely than patients with just a loss of taste to have Covid-19 antibodies, and participants with a combined loss of smell and taste were four times more likely to have antibodies.
“These findings suggest that a loss of smell is a highly specific symptom of Covid-19, in contrast to a loss of taste, despite their comparable frequency,” the researchers wrote.
The study recruited its volunteers between April 23 and May 14, during the peak of the Covid-19 outbreak in London. It did not include a comparison group of people who did not lose their sense of smell and/or taste.