Loss of taste/smell could be the best indicator of COVID-19 and be long-lasting

Editor’s note: This article was published on April 17, 2020. COVID-19 information and recommendations are subject to change. For the most up-to-date information, visit the Centers for Disease Control and Prevention (CDC) website or view our most recent COVID-19 blog posts.

It seems as if COVID-19 has been around for years, but still so new at the same time.

As the novel coronavirus (COVID-19) pandemic spread around the globe, scientists in Britain may have discovered the best way of detecting if someone has COVID-19 – the loss of taste and smell.

Marshfield Clinic Health System otolaryngologist, Timothy Boyle, M.D., agrees, calling the loss of smell or taste “perhaps the best and most accurate indicator of having COVID-19.”

“We have nearly 75 percent of people who are COVID positive reporting the loss of smell or taste. Those two are intermingled,” he said.

A sudden loss of smell and/or taste, in the absence of other upper airway inflammatory diseases should be a good indicator to be tested for COVID-19. According to the Vanderbilt University Medical Center, smell loss is one of the first — and sometimes only — symptoms in up to 25% of people diagnosed with COVID-19.”

The American Academy of Otolaryngology-Head and Neck Surgery gathered anecdotal information through an online reporting tool to find out more.

Other parts of the world seeing similar symptoms

Primary symptoms listed by the U.S. Centers for Disease Control and Prevention are familiar at this point. These include fever, new cough and shortness of breath not associated with prior chronic condition or allergies. The list has and continues to get longer and the new loss of smell and taste is now listed as a symptom of COVID-19.

As more cases come back with loss of smell and taste as a symptom, the more it’s being investigated. Boyle said, in Germany, 60% of the COVID-19 cases reported anosmia (decreased sense of smell). He also said that new surveys show in the most recent months nearly 75% of all cases, report recent loss of taste or smell was a symptom experienced.

Not only is it the most likely indicator of COVID-19, but those lack of senses can be long-lasting, Dr. Boyle said.

“Patients are reporting extended period of loss of smell and taste,” Boyle said. “You contract COVID-19 in, say, September and they still don’t have it back or it goes in and out.”

In areas of the world that have had large numbers of COVID-19 cases like China, Italy, South Korea and Iran, it has been observed that significant numbers of patients who test positive have had a decreased sense of smell.

While there has been a high positivity rate in many parts of the world, the loss of smell and taste varies widely depending on what country or who is studied.

According to a study in the US National Library of Medicine National Institutes of Health, during the COVID-19 outbreak, frequency of sensory disorders (smell and/or taste) in affected patients has shown a high variability from 5 to 98%, depending on the methodology, country, and study.

At the Health System, Boyle said information gathered and updated is being taken seriously.

“It is well known that common viruses (including known strains of coronavirus), that cause routine cold-like illnesses, can damage the sense of smell temporarily or permanently,” he said. “The reason we use nasal swabs to detect the novel coronavirus is that the lining of the nose and the back of the nose contain the highest levels of the virus. Therefore, it isn’t surprising to think that a loss of smell would potentially be caused by COVID-19.”

Convincing evidence

The most convincing evidence comes from King’s College in London, Boyle said. British scientists collected data from 1.5 million people using a symptom tracker app used to monitor the pandemic spread. Just like in Germany, they found that 60% of patients who eventually tested positive for COVID-19, complained that they had lost their sense of smell or taste. Those who did were three times more likely to test positive for COVID-19 when they also suffered other symptoms.

“Thus, the American Academy of Otolaryngology has made a recommendation to use loss of smell as a screening symptom for otherwise asymptomatic patients,” Boyle said. “This could allow early quarantine of these patients and slow the spread of the virus. It also could allow those of us in otolaryngology to more accurately predict when to use scarce supplies of maximal protective equipment.”

Do you think you have symptoms of COVID-19? Contact the Health System’s Nurse Line at 1-844-342-6276 before visiting your doctor’s office or urgent care.

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