Peel-and-Sniff Cards Could Make Smell Test Single Best Predictor of Being COVID-19 Positive

Sensory scientists are encouraging smell checks to fight the COVID-19 spread and are also developing peel-and-sniff cards to supplement other COVID-19 testing and surveillance efforts.

With mounting scientific evidence that anosmia, or loss of smell, is one of the most specific symptoms of COVID-19 infection, sensory scientists at the Pennsylvania State University (University Park, PA, USA) are making efforts to raise awareness about the link between COVID-19 and smell loss. Previous research has found that certain cells at the top of the nasal cavity harbor proteins that the coronavirus targets when invading these cells. The local disruption that occurs is different from the loss of smell that occurs with the common cold, which is due to blockage of the nasal passages. With COVID-19, many patients lose the ability to smell without being stuffy or congested.


The sensory scientists at Penn State believe that greater public awareness of the link between COVID-19 and sudden smell loss could assist in identifying pre-symptomatic or otherwise asymptomatic individuals, which might help contain the virus and ease the burden on sometimes-overwhelmed health care facilities. Additionally, the scientists are members of an international research team, the Global Consortium for Chemosensory Research, that has studied the link between COVID-19 and smell loss. Collaborating with more than 600 clinicians, scientists and patient advocates in 40 countries in an ongoing study, the Penn State researchers so far have surveyed more than 40,000 participants who suffered from recent respiratory illness. The scientists are now developing peel-and-sniff cards that will be distributed to the Penn State community in the near future to supplement other COVID-19 testing and surveillance efforts.

"Our results showed that of all common symptoms of COVID-19, sudden smell loss was the single best predictor of being positive for the disease," said John Hayes, professor of food science and director of the Penn State Sensory Evaluation Center. "Other studies are finding similar results. Together, this suggests that sudden smell loss is a better predictor than fever or cough."

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