Loss of smell more common in Covid-19 than thought

  • Subjective reporting underestimates the true prevalence of smell loss in Covid-19
  • Measuring loss of smell may be an effective tool for diagnosing Covid-19 early on
  • Study authors suggest measuring people for smell loss may become as routine as measuring body temperature for fever


Loss of smell is common in Covid-19, but fewer people say they have this symptom than objective tests reveal, a new study finds.

In fact, about 77% of Covid-19 patients who were directly measured had smell loss, but only 44% said they did, researchers found.

Direct measures of smell involve having patients smell and report on actual odours, while self-reporting includes getting data through patient questionnaires, interviews or electronic health records, the study authors explained.

Effective tool for Covid-19 diagnosis

"Objective measures are a more sensitive method to identify smell loss related to Covid-19," said study co-author Mackenzie Hannum, a postdoctoral fellow at Monell Chemical Senses Center in Philadelphia.

Subjective measures, "while expedient during the early stages of the pandemic, underestimate the true prevalence of smell loss," said Vicente Ramirez, a doctoral student at the University of California, Merced, and summer intern at Monell.

The research suggests subjective measures underestimate the true extent of smell loss and that it may be an effective tool for diagnosing Covid-19 early, the authors said in a Monell news release.

For the study, the researchers reviewed previously published studies on Covid-19 and loss of smell.

Their findings were published online recently in the journal Chemical Senses.

Senior author Danielle Reed, associate director at Monell, suggested that "measuring people for smell loss may become as routine as measuring body temperature for fever".

Image credit: Getty Images

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