Before the pandemic, Dr. Jennifer Spicer liked to wake up early. In those quiet hours of the morning, she would have precious time alone with her dog and prepare a mug of her favorite coffee, using beans from an Atlanta toaster.
Now she can barely take a sip without spitting the coffee. Once a source of gustatory pleasure, your coffee now has a chemical smell and taste that Spicer can no longer tolerate.
“I can’t even go into a cafe. It smells so bad,” said Spicer, an assistant professor of infectious diseases at Emory University School of Medicine. “It’s really awful.”
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The abrupt change in Spicer’s senses now has a very common culprit: Covid-19. She had a relatively mild case of the virus last summer; in addition to losing his sense of taste and smell, he also had fever, chills and tiredness for about a week. Your sense of smell and taste has finally returned – but not as before.
Well, said Spicer, certain foods and drinks smell and taste bad. Too bad.
“It ranges from an unpleasant chemical taste to a taste of rotten meat,” said Spicer, adding that a recent bite of cheese tasted like chalk. Things are starting to get better, but it’s been almost six months since she was infected.
Spicer is far from alone. A study published on Wednesday in the Journal of Internal Medicine found that 86% of patients with mild forms of Covid-19 developed loss of taste and smell, compared with 4% to 7% of those with moderate to severe cases.
The survey included more than 2,500 patients in France, Belgium and Italy. Most regained consciousness in about two months.
Why loss of smell and taste are more common among people with milder forms of Covid-19 remains unclear. The study authors theorized that these patients have higher levels of certain antibodies that can limit the spread of the coronavirus to the nose.
A different line of attack
Covid-19 is not the first disease to cause loss of taste or smell. A bad cold, the flu and even bad allergies can cause nasal congestion that makes these senses useless. But in these cases, using a decongestant can help, even if only temporarily.
Not so with Covid-19, experts say. Instead, the coronavirus dulls these senses through a different line of attack.
“This is an inflammatory process in the nerve itself or in the cells,” said Dr. Nina Shapiro, a pediatric head and neck surgeon at UCLA School of Medicine.
A person’s sense of smell works like this: an odor molecule enters the nose and lands on a special type of tissue called the olfactory epithelium. This tissue is full of neurons, which take the odor molecule and transport it through the olfactory bulb to the brain, where it is interpreted as, say, the smell of roses.
Neurons are guided on this journey from the nose to the brain by support cells that act as signaling boards, pointing the way. But the supporting cells are covered by a receptor called ACE-2 – the main target of coronavirus in human cells. This also makes support cells a prime target.
Experts hypothesize that the virus lodges in these cells, interrupting the path for neurons to reach their destination in the brain. When that happens, people lose their sense of smell. And the smell is directly linked to the way a person experiences the taste.
There is no guarantee that these nervous connections will ever find their way back to their normal pathways. But the fact that at least some reaction is taking place – even if it means that an odor once appreciated now smells like chemicals – may be a good sign.
“In fact, we think these nerve endings are trying to grow and repair themselves,” said Dr. Bradley Goldstein, associate professor of head and neck surgery and communication sciences at Duke University School of Medicine, North Carolina. “They are not sending the right signals yet, but things need to be cured.”
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The smell and taste of food are not the only sensory problems for people who have had Covid-19. Patients also had to change scented soaps, detergents and deodorants.
Loss or change of smell can be irritating, yes, but Shapiro points out that it can also be dangerous.
“If you have a gas leak, you can’t necessarily smell it,” she said. And if people lose their appetite because the food tastes like cardboard or even rotten meat, they can develop vitamin deficiencies. Furthermore, people may not know when the food is, in fact, spoiled or even burning.
The other risk, said Shapiro, is depression. People take great pleasure in eating and drinking, as well as in other basic aspects of human happiness, like smelling flowers.
“Your nose influences your emotional state. It helps us navigate our world and makes us feel that we are in the right place,” said Dr. Sandeep Robert Datta, associate professor of neurobiology at Harvard Medical School.
“People who lose their sense of smell are at real risk for psychological disorders, including depression,” he said.
Spicer, now six months in his own sensory problems, advises those in similar situations to seek support groups. “Read about other people’s experiences, because it makes you feel less crazy,” she said.
“Honestly, you start to ask yourself, ‘Am I being dramatic? Is it that bad? ‘
“Yes,” she said. “It really smells so bad.”
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