The nose knows that coronavirus is present – at least in about 60 percent of those infected. Although this early-warning system hasn’t been noticed much in China, it has been recognized in Israel, France, Iran and in other countries affected by COVID-19.
Along with fever, cough and shortness of breath – many coronavirus) patients report a temporary loss of their sense of smell. It appears that olfactory (sense of smell) loss is significantly greater in such patients compared to the loss that is often experienced during a cold and less commonly, in non-COVID-19 influenza patients.
In some countries, such as France, a patient who claims to have a sudden onset of olfactory loss will be diagnosed as a coronavirus patient – without even being tested. A similar approach is being considered in the United Kingdom.
Based on this data, researchers at the Weizmann Institute of Science in Rehovot, in collaboration with the Wolfson Medical Center in Holon (south of Tel Aviv) developed an online platform called SmellTracker. It enables self-monitoring of an individual’s sense of smell for the purpose of detecting early signs of COVID-19 or in the absence of other symptoms.
The lab of Weizmann neurobiology Prof. Noam Sobel, who is head of Weizmann’s Azrieli National Institute for Human Brain Imaging and Research, specializes in olfactory studies. The researchers previously developed a mathematical model that accurately characterizes a person’s unique sense of smell – a kind of personal “olfactory fingerprint.” Based on this algorithm, SmellTracker guides users on how to map their sense of smell using five scents found in every home (spices, vinegar, toothpaste, various scent extracts, peanut butter and the like).
The odor test, which lasts about five minutes, is able to monitor sudden changes in odor perception that may be an early indication of the onset of COVID-19 disease. The researchers report that the tool they developed has already successfully identified potential coronavirus cases that were later confirmed. Aside from personal monitoring, as more data is collected, the researchers are more likely to be able to characterize a unique olfactory fingerprint for the early detection of COVID-19.
Olfactory loss was not commonly reported in the city of Wuhan, China, where COVID-19 first broke out. Nevertheless, preliminary studies conducted in several countries, including Israel and Iran, show that this symptom appears in about 60% of patients. Scientists estimate that there are currently eight active strains of coronavirus. Sobel’s lab believes that olfactory loss may be a differentiating symptom of the various strains. If this turns out to be true, the SmellTracker will be able to map the various outbreaks geographically.
Besides SmellTracker, Sobel’s lab is distributing “scratch and smell” kits among confirmed coronavirus patients to map their sense of smell, as well as a unique questionnaire.
The venture, which was launched with backing from Israel’s Defense Ministry, will be officially promoted in the coming days in Sweden, France and other countries. The scent test is currently available in English, Hebrew and Arabic, and it will also be available in Swedish, French, Japanese, Spanish, German and Persian.