In a Facebook group of over 10,000 members, called “COVID-19 Smell and Taste Loss,” people from all over the globe are sharing their stories of this puzzling coronavirus symptom.

One member, Rhian Cadwaladr, is a cookbook writer based in Wales. A week ago, she made a shortbread that tasted quite strange to her. Wondering what could have happened, she went around the house tasting various foods. Suddenly, all of the sweet items, from biscuits to plain sugar, “began tasting bitter and poisonous,” she told Medical Daily in an interview.

Ms. Cadwaladr has since taken two COVID tests, both of which came back negative. But she suspects the virus was passed to her through an asymptomatic carrier.

She worries that this change in her ability to taste food could affect her career in the food industry. “I cannot even imagine a life with a limited diet, as food is my passion — cooking it and eating it.”

Other long-standing members of the group say their symptoms have lasted for five, six or seven months – the length of the pandemic -- some with no signs of resolving. Their loss of taste and smell have caused a range of other effects as well, from a lingering bad taste in the mouth to the feeling of the nose being blocked for days on end.

According to the US National Institutes of Health, olfactory (smell) and gustatory (taste) receptors allow the body to differentiate between wide ranges of smells and tastes. Putrid or flowery, sweet or spicy, smells and tastes are triggered by receptors in the nose and mouth. Harvard Medical School (HMS) describes loss of smell as the leading neurological symptom, and one of the most commonly reported markers, of COVID-19.

In a study conducted by HMS, researchers found that olfactory cells in the upper nasal cavity are the most vulnerable to SARS-CoV-2, the virus that causes COVID-19.

“Our findings indicate that the novel coronavirus changes the sense of smell in patients not by directly infecting neurons but by affecting the function of supporting cells,” said senior study author Sandeep Robert Datta, MD, PhD, in an HMS report on the study. Dr. Datta is an associate professor of neurobiology in the Blavatnik Institute at HMS.

That loss of smell and taste often leads to mental and social health issues, specifically depression and anxiety.

A study published in The Laryngoscope in July furthers this evidence with a study of 114 COVID-positive patients at a hospital in Aarau, Switzerland. One in four of these participants reported that loss of smell was their first symptom of the virus.

Participants then filled out a questionnaire regarding their mental health. Researchers found that depressed mood and anxiety were positively associated with loss of smell and taste. The other symptoms of COVID-19, such as fever, coughing or shortness of breath, were not shown to cause depressed mood or anxiety.

The good news is that the loss of smell and taste due to COVID-19 are likely to return, according to Dr. Datta. He said once the infection clears, the olfactory cells affected don’t appear to need to be replaced or rebuilt.

Chrissi Kelly, the head of the “COVID-19 Smell and Taste Loss” Facebook group, told Medical Daily that she intends to inspire this hope of recovery by bringing together affected patients.

In 2012, years before the COVID-19 pandemic, Ms. Kelly lost her sense of smell due to a different virus that impacted her sinuses.

She began taking courses on “smell training” with Thomas Hummel, MD, the leading researcher in the field. She began hosting smell and taste loss Facebook groups in 2015, in order to provide people with the resources she didn’t have when she lost her sense of smell.

According to Ms. Kelly’s organization AbScent, smell training can be described as “physiotherapy for your nose,” which is not a cure for the lapse of smell but a way of enhancing recovery. Techniques include the use of smell-training kits to ease different scents back into your sense of smell.

When the COVID-19 pandemic exploded in late February, and the conversation began to grow, Ms. Kelly started a new Facebook group for people with COVID-19 who had lost their senses of taste and smell. The next morning, the group had already reached 1,000 members.

The group has become an outlet for members to find resources, ask questions, crowdsource and consult with experts.

Above all, said Ms. Kelly, the Facebook group’s main focus is to improve people’s lives.

Lara Becker is a Medical Daily intern and a senior at The College of New Jersey studying Journalism/ Professional Writing and Communication Studies.