A new study has revealed that most COVID-19 patients experience loss of smell and taste by the third day of coronavirus infection. At least 61% of the patients reported reduced or lost sense of smell to the study conducted at Kantonsspital Aarau in Aarau, Switzerland.
The news comes after a previous study from University of California (UCSD), which found that taste and smell loss were among the first symptoms to appear in COVID-19 patients. Unfortunately, these symptoms don’t always resolve immediately after a patient recovers.
In a recent report to Science Daily, Dr. Carol H. Yan, an otolaryngologist-head and neck surgeon, and assistant professor of surgery at UCSD Health, suggested people with smell and taste loss were 10 times more likely to have a COVID-19 infection than other causes of infection.
“[Our] study is the first to demonstrate the association of smell and taste loss in patients who were test-confirmed COVID-19 positive compared to those who were COVID-19 negative,” Yan tells Parentology. “Meaning, all these patients had presented with flu-like symptoms and concerns for COVID-19 but those who had smell/taste loss specifically were much more likely, 10 times [more likely], to be positive for coronavirus.”
Yan adds, “In our study, we found that smell and taste loss were among the first symptoms presented in about 20% of patients who tested positive for COVID-19. Overall though, almost 70% of our patients with coronavirus reported loss of smell and taste during their illness.”
The new study in Switzerland also connected the severity of the loss of smell to how severe other coronavirus symptoms are. If the loss of smell was worse, patients reported more severe shortness of breath, fever, and cough.
The study also linked new symptoms to COVID-19 patients — stuffy and runny noses, which are typically associated with the common allergy and not COVID-19. According to the study, about 50% of the patients reported a stuffy nose and 35% of patients reported a runny nose.
“This just means that greater awareness is needed of COVID-19’s nasal symptoms so people are not running around sneezing in public and thinking it is okay since this is just allergies,” said Ahmad Sedaghat, MD, PhD, principal investigator of the study, Eureka Alert writes. “It very well could be COVID-19 and wearing masks as protective gear for others you encounter is a good idea.”
Why This Happens
In a recent interview with US News & World Report, Dr. Steven Munger of the University of Florida’s Center for Taste and Smell explained there are three possible reasons behind COVID-19’s disruption of the sense of smell. The first is that COVID-19 may damage the olfactory nerve in infected patients. A second speculation is that the virus targets sensory nerves, thereby “damaging or mucking up the works” of nerves in patients with COVID-19. A third theory is that the virus invades the nasal passages, leading to symptoms that interfere with the ability to smell.
The study conducted in Switzerland found that there was women and younger patients were more likely to experience a decreased loss of smell.
Noticing Loss Is Important
To prevent further spread of the illness, early identification of the subtle symptoms of COVID-19, such as taste and smell loss, is essential. Yan hopes that, with an increased awareness of the mild symptoms linked to COVID-19, carriers of the virus will recognize their role in transmitting the disease and stay home to prevent infecting others.
“It is our hope that, with these findings, other institutions will follow suit and not only list smell and taste loss as a symptom of COVID-19,” Yan says, “but use it as a screening measure for the virus across the world.”
“We found that, in the non-hospitalized COVID-19 patients (those [with] more mild symptoms), people typically recovered from their other symptoms of COVID-19 a little sooner than [they recovered] their sense of smell/taste,” Yan says. “However, promisingly, most people with COVID-19 associated smell and taste loss tended to show improvement after two to three weeks.”
While other upper respiratory infections can cause permanent damage to the sensory nerve cells that control smell, smell loss associated with COVID-19 seems to be temporary. “A complete recovery may take some time, however, even after all other symptoms of the disease have gone away,” Yan says.
Although the connection between COVID-19 and smell loss still remains anecdotal in nature, current findings suggest that smell training may be a promising way to help restore sensory functioning in those who lost it due to COVID-19. What this means? Munger told CNN that frequently smelling items – like candles, shampoos, and lemon juice — around the house multiple times a day may help stimulate a response in the sensory nerve cells that were damaged by the infection. Munger said this exercise could potentially help the brain “focus on the amount of smell function that is still intact.”
Coronavirus Smell and Taste — Sources
Dr. Carol Yan, otolaryngologist-head and neck surgeon assistant professor of surgery at UCSD Health
CDC Symptom Checklist for COVID-19
Yan’s Research Study
UC San Diego Press Release
US Health & World Report