The researchers, based in the United Kingdom, wrote in their study that people who lose their sense of smell or taste should consider isolating themselves, even if they have no other symptoms.
The team studied 590 volunteers who experienced a new odor or taste, and they tested 567 of them for Covid-19.
Nearly 40% of those tested positive for antibodies had no fever or cough.
Batterham and his colleagues also found that participants with only odor loss were almost three times more likely than patients with only loss of taste to have Covid-19 antibodies, and participants with combined loss of smell and taste is four times more likely to have antibodies.
“These findings suggest that an odor loss is a specific specific symptom of Covid-19, as opposed to loss of taste, despite their comparable frequency,” the researchers wrote in the study.
The study recruited its volunteers between April 23 and May 14, during the peak of the Covid-19 outbreak in London. The findings have some limitations, including that the study did not include a comparison group of people who did not lose their sense of smell and / or taste.
At the time, a government statement said “all individuals should be isolated if they develop a new persistent cough or fever or anosmia.”