COVID-19 patients show loss of the sense of smell, a symptom which is most likely to occur by the third day of infection with the novel virus, according to researchers.
Most of these patients are also experiencing a loss of the sense of taste, they said in their study after conducting characteristics and symptoms of 103 patients who were diagnosed with COVID-19 over a six-week period at Kantonsspital Aarau in Aarau, Switzerland.
Patients were asked on phone how many days they had COVID-19 symptoms and also asked to describe the timing and severity of loss or reduced sense of smell along with other symptoms.
At least 61 per cent of the patients reported reduced or lost sense of smell, said Ahmad Sedaghat, an associate professor in the UC College of Medicine's Department of Otolaryngology-Head and Neck Surgery and an UC Health physician specializing in diseases of the nose and sinuses, who was the principal investigator of the study.
The mean onset for reduction or loss in the sense of smell was 3.4 days.
The findings have been published in the journal Otolaryngology-Head and Neck Surgery. The first author of the research was Marlene Speth, at the Switzerland hospital.
"We also found in this study that the severity of the loss of smell is correlated with how bad your other COVID-19 symptoms will be," said Sedaghat. "If the anosmia, also known as loss of smell, is worse, the patients reported worse shortness of breath and more severe fever and cough."
Sedaghat explained that, "Our study indicates that a decreased sense of smell may be an indicator of patients early in the disease course as well as those who may go on to develop more severe symptoms, like shortness of breath, later on.”
He cautioned that while the loss of smell is an indicator of COVID-19, it's not the only factor. "When you start to experience serious symptoms of COVID-19 which include shortness of breath and respiratory distress, that's when you should become alarmed." The study also found that younger patients and women in the study were also more likely to experience a decreased loss of smell, said Sedaghat.
Also, about 50 per cent of study patients experienced a stuffy nose and 35 per cent experienced a runny nose. Sedaghat said it was important because previous studies indicated that these nasal symptoms were rare in COVID-19 and these symptoms were attributed to allergy and not the novel coronavirus.
"No one is going to die because of a loss of the sense of smell and it's not the symptom that will kill anyone," said Sedaghat. "However, it is important because it helps us to identify these COVID-19 patients as asymptomatic carriers so they don't spread the disease to others. Now we can potentially identify them early during the disease to start antiviral medications and ultimately maximize our ability to effectively treat these patients."
Other co-authors of the study included Isabelle Gengler, UC Department of Otolaryngology-Head and Neck Surgery, along with Thirza Singer-Cornelius, Michael Oberle, and Steffi Brockmeier, all from Kantonsspital Aarau.