A sudden loss of smell and taste—particularly without signs of a cold or allergies—may signal COVID-19 infection. This finding comes from a King's College London study using data from a symptom-tracking app. Nearly 60% of confirmed coronavirus carriers reported these sensory losses.
In contrast, 18% of those reporting loss of taste and smell tested negative. The results, published online on April 1 (not yet peer-reviewed), draw from 1.5 million app users between March 24-29. Of these, 26% reported symptoms; 1,702 had tested—579 positive, 1,123 negative.
Researchers built a mathematical model analyzing symptom combinations—including loss of smell, loss of taste, fever, persistent cough, diarrhea, fatigue—to pinpoint infection likelihood.
"Combined with other symptoms, loss of smell and taste makes individuals three times more likely to have COVID-19. They should self-isolate for seven days to reduce disease spread," said lead researcher Prof. Tim Spector.
