In Search of Lost Smell and Taste

Sasha von Oldershausen
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I remember the moment I lost my sense of smell and taste, like the flick of a switch, on a Zoom call with old college friends, one in Atlanta, the other in Chicago. We all had drinks. That was during the time, in late March, when everyone was drinking and no one felt bad about it. I’d made a Campari spritz, my newfound infatuation with aperitivos inspired by a trip I’d made to Italy only a little over a month earlier—my last trip. 

I took a sip and realized I couldn’t taste its bitterness. Then I bit into a potato chip and perceived only the astringent sensation of sodium. You never realize the complexity of a single potato chip until it’s stripped down like that. I didn’t say anything, and continued to drink my spritz, happy to find that the alcohol still hit. After the call, I chalked it up to allergies. I had no other symptoms except for a mild cough and a burning sensation in my upper sinuses (also allergies).

By my second week without smell or taste, it had become widely known that this was a common symptom of COVID-19. Everything moved so fast then. It was difficult to concentrate on anything other than the shrill transmission of disaster, eyes flitting across the page, fingers scrolling, searching for new information that seemed only to contradict the old. 

Once I’d come to terms with my reality, I considered myself lucky to live in Queens, New York, at the time the global epicenter of the virus, where everyone was dying or losing, and to have lost only this.

The story goes that as we evolved from walking on all fours, our dependency on our noses also evolved, as our noses were no longer so close to the ground. Others say it was when our vision evolved from dichromatic to trichromatic—that is, when we developed the ability to perceive red, blue, and green—that our olfactory system lost its precedence, superseded by sight. 

For most animals, smell is the most important sense. A full third of a mouse’s brain is devoted to smell, a faculty without which the mouse would certainly starve to death. In the case of humans, a third of our brains is devoted to vision. It’s commonly believed that canines possess a sense of smell nearly a thousand times more potent than ours. (I recalled this bit of trivia years earlier when I lived on the Texas–Mexico border, a swath of land punctuated by Border Patrol checkpoints on the Texas side, where agents stood by with German shepherds trained to sniff out passing vehicles for drugs or people not in plain sight.) 

Despite this evolutionary proclivity to sight, smell remains a vital sense that helps humans avoid situational danger. Noxious air caused by a gas leak triggers the body’s nervous response system, while putrid smells like those emitted by feces, vomit, or spoiled foods repulse us, discouraging us from interacting with potential biohazards. While wildfires raged in California, the smell of smoke triggered PTSD in residents who’d come to understand the destruction caused by burning as a recurrent reality. Smell is also tied to human attraction, while kissing—that wet, tingling surge of touch sensation—is, in fact, thought to have developed from sniffing, a way of smelling and tasting our partners to know if they’re a good fit. 

And nowhere is our olfactory system as pronounced as in its connection to emotion and memory. Recall Marcel Proust and his tea-soaked madeleine, which was enough to inspire his more than four-thousand-page opus to memory, In Search of Lost Time. Though most readers will attribute the potency of this literary moment to taste, most of what we consider flavor is, in fact, molecules making their way back to us through our nasal epithelium. Which is to say, Proust’s madeleine-induced memory was really just his nose at work.

Yet for all its myriad functions, smell is still one of the least appreciated senses. When asked which of the five senses they would most readily give up if they had to choose one, almost no one chooses sight or hearing, and loss of touch is synonymous with loss of sexual pleasure.

“Everyone says smell,” says Pamela Dalton, a cognitive neuropsychologist at the Monell Chemical Senses Center, a nonprofit scientific institute in Philadelphia dedicated to interdisciplinary research on the senses of taste and smell. When I speak to her over a Zoom call in August 2020, Dalton tells me that Philadelphia’s sanitation department has been struggling to keep up with its trash pickup during the pandemic. “It’s pretty smelly out there,” she tells me, and explains that we can typically smell better in warmer weather because heat makes odor molecules more active in the air. “Trash strikes in February are a lot better [for residents] than ones in August,” she says. 

Dalton has a good nose. Before the pandemic, she traveled far for work; she’d always bring a little atomizer with her filled with the smell of something that reminded her of home, which she’d spray on her pillow before she went to sleep. “That way, when I closed my eyes, it just calmed me,” she says. (Her line of inquiry focuses on the brain’s response to smell and how human emotion ties to olfaction.) 

For someone whose research seems so specific, Dalton’s work is surprisingly versatile. She’s collaborated with artists on smell-specific installations and worked on an indoor sanitation initiative in a region of India. She participated in a project with NASA in which lab mice were sent to outer space to see whether the enclosed chambers that contained them could also effectively contain the smell of their notoriously malodorous urine—a prohibitive factor for experiments involving mice in space. Astronauts can be real divas, Dalton says, though in this case, they became enamored with watching the mice as they navigated their microgravity environment, turning somersaults in their capsules the way astronauts do.

Since the emergence of COVID-19, the Monell Center has had its work cut out for it. Over the past several months of the pandemic, the loss of smell and taste has emerged as one of the most reliably predictive symptoms of COVID-19, though the exact statistics still vary widely, with studies showing that anywhere between 50 and 90 percent of patients report some degree of smell and taste loss—more than the number of patients who report fever, cough, or respiratory difficulty.

When the team at the Monell Center discovered that loss of smell and taste could better predict COVID-19 than its other associated symptoms, they realized they should be screening people for it. The center had previously worked to develop a National Institutes of Health–funded odor test comprising a series of nine odor cards that subjects would smell and then match with corresponding images—a cup of coffee, a lemon. 

Now the center is trying to devise a scaled-down version that could be used as an additional screening measure for COVID-19, in the same way that many private businesses and public institutions have adopted the system of taking their patrons’ temperatures upon entry. There are certain challenges to developing a test of this kind, since acuity of smell varies widely from person to person. The more an individual uses the test, however, the more fine-tuned it becomes to that person’s smelling ability. As a result, the center determined that frequent testing is the best way to ensure accuracy. “If you performed this way on Tuesday and all of a sudden on Friday your performance looks very different, it could be a flag to say you shouldn’t go into work and you should probably get tested,” Dalton said.

The scientists at the Monell Center are not the only ones working on this kind of research. In response to the pandemic, a community of smell researchers in labs across the globe mobilized and formed the Global Consortium for Chemosensory Research, which conducts scientific studies to assess the possible relationships between respiratory illnesses and their effects on smell and taste. The consortium also offers a data-collection survey on its website, as well as a self-check test using household items such as burned matches, sunscreen, and cat food. Before the emergence of COVID-19, loss of smell, medically referred to as anosmia, was associated with certain viral illnesses or head trauma. Research has also shown anosmia to be an early onset indicator of both Parkinson’s and Alzheimer’s disease. But it’s safe to assume that never before has smell loss affected such a broad swath of the population, or quite so suddenly.

 “This unprecedented spread of olfactory and gustatory alterations in the population may bring a never experienced awareness of how important these sensory modalities actually are for one’s psychological functioning, including one’s emotions, especially emotions elicited by food,” a study by Nature Partner Journal Science of Food stated. In other words, smell might finally be having its moment.

Back in Queens, at the start of my scentless journey, I tried to turn my weakness into a strength, to make lemonade out of lemons, so to speak (though at the time, I could taste neither lemons nor lemonade): I would clean out my fridge and not get grossed out by all the strange, forgotten things in the back. I unearthed Thanksgiving gravy that had turned blue, a Tupperware of dull-looking chicken, a carton of spoiled milk, thick with curdles. Spinach that had already composted in its plastic clamshell. I couldn’t smell any of it. 

I couldn’t smell the litter box when I cleaned it, or my cat’s breath as he yawned in my face; since lockdown began, he seemed more bored by me than usual. Nor did I feel the accompanying guilt I associated with the smell of stale cigarette smoke on my fingertips. The loss of taste was more of a drag—food loses its allure when the sole measure of palatability is its texture—though that had certain perks too. I could avoid quarantine weight gain because there was no reason to eat other than for sustenance.

At some point, a stray cat found its way into my ceiling and died there; my only clue was the sudden barrage of flies that descended upon my apartment. When my brother came over to help investigate, he held his hand over his nose. “Oh god, that’s awful,” he said, while I’d been living in the stink for days.

After a month, my sensory loss lost its novelty. When my friend Daphne told me she’d also lost her sense of smell and taste but that she’d recovered them only a couple of weeks later, I started to panic. Why hadn’t mine returned? What if my senses were permanently damaged? I scoured the internet, unearthing horror stories about the possible neurological fallout of the virus, the as-yet-unknown consequences of this sickness. There was a story of deep-sea divers who’d had only mild symptoms of COVID-19, but when they went in for check-ups they discovered they had broad scar tissue damage across their lungs. Again and again, the examples only proved how much we still didn’t know.

It might have been less alarming if not for my particular relationship to smell, which I’d considered my most potent sense, especially after I ruined my hearing through overexposure to loud experimental pop and hip-hop in my early twenties, the bass lines throbbing through my pair of blown-out headphones and competing with the screech of metal on my hours-long subway commute. My eyesight was damaged from the start; I had glasses by the second grade, and by now can see only the vague outlines of shapes without my contact lenses. 

While my other senses deteriorated over time, my sense of smell matured and intensified. I found that the more I smelled things, the more discerning my nose became. I could identify spice profiles from a single whiff of a dish; on my walks home from school, I used to play a game of figuring out what my mother was cooking for dinner within a block of our house. 

Like Proust, odors were my clearest point of entry to memory, recalling vivid childhood moments—that winter when I had a terrible cold and my father rubbed Vicks VapoRub into my chest; those long car rides with my mother’s perfume thick in my nose. When she left for weeks at a time to visit her family in Iran, I would sneak into her room and bury my face in her pillows, still infused with the sweet but fading fragrance. 

My mother, whose sense of smell is perhaps even more pronounced than mine, is likely my olfactory progenitor. Maybe it’s our big Iranian noses. (A study involving CT scans of people’s noses showed that the anatomy of our nose affects the ability of odor molecules to access our smell receptors. On average, 10 percent of odor molecules reach our smell receptors, though for some, as much as 30 percent can make their way there.) 

At times, my sense of smell edged on the sensual. “I have the nose of a bloodhound,” I used to tell people. I once followed a woman across lower Manhattan because she smelled like my high school boyfriend, years after we’d dated. 

The connection between olfaction and sexual arousal has been documented. Pheromones, those airborne molecules that all humans secrete and that linger in the nostrils of people in close contact, can be powerful aphrodisiacs. Studies have shown that pheromones emitted by mice have the ability to attract mates who are otherwise genetically similar, except for their differing immune system genes, the combination of which would give their offspring a necessary edge in fighting disease. A Swedish scientist who sought to replicate this study in humans had a group of women smell the sweaty T-shirts worn by a group of men and found that, as it had for the mice, scent was an effective transmitter of genetic information: overwhelmingly, the women preferred the scent of those men whose immune system genes varied from their own. 

At the same time that I was coping with the fallout from my sensory loss, I was falling in love with a man I’d met only briefly before the pandemic, though not long enough to sniff him or to kiss him. Consigned to our respective pods, we talked nightly, for hours at a time, sometimes on the phone, sometimes on video calls. Because he lived with his immunocompromised sister, there was no chance I’d see him in person for months to come. 

During that period, his voice became a deep comfort to me. I would lie down in bed with the lights out, like in a sensory-deprivation chamber, my ear hot from pressing it against the speaker of my phone, a deep abyss from which his voice would sound, flooding me with endorphins. Without sight, I found myself paying closer attention to his words, a sanctified experience so far removed from the complications of modern-day dating. Apart from our calls and my daily walks with a designated quarantine friend, I spent my days in total solitude. 

I’d always considered myself well-groomed for isolation; early in lockdown, as the term quarantine infiltrated the everyday vernacular, I joked that as a writer, I’d been quarantining for most of my life. But this was different. Those long nights, I sat on my couch, alone in my apartment, a glass of something beading with condensation drawing rings like moon cycles on my coffee table. The depth of my isolation felt wholly at odds with the atmosphere of collective grief that inspired a need—desperate and inexorable—to connect to others. The loss of smell sent me reeling, as I suddenly found myself stripped of the tool that most acutely offered that feeling of connectedness.

One night, hours into one of our calls, the voice on the other line told me he had color blindness, a hereditary condition—in his case passed down by his father—that affects one in twelve men; his brother was similarly afflicted. He explained that colors appeared less saturated than they would to a person with normal vision and that he sometimes had trouble discerning subtle differences in shade. He didn’t get all the fuss about sunsets. Unlike me, though, he didn’t perceive his deficiency as a loss, because he’d never had the opportunity to know the alternative. 

When I explain my symptoms to Sandeep Robert Datta, an associate professor in the Department of Neurobiology at Harvard Medical School (and who insists I call him Bob), I sense excitement in his voice. It’s early fall, nearly half a year since I lost my sense of smell. Like Pamela Dalton and other scientists studying smell, Datta shifted the goals of his research in response to the pandemic. “Our suspicion is that as we begin to dial in more and more objective measures—as people go to smell clinics and we can formally quantify people’s sense of smell—we’ll learn that COVID affects 80 percent of people or more in terms of their sense of smell,” Datta says. “It’s not just the majority; it’s the vast majority. And to some extent, it could be everyone.”

Datta, who laments his own nose’s general lack of acuity, given how much pleasure he receives from wine and perfume, tells me that while most of the data currently available derives from patient self-reports, and is therefore largely anecdotal, certain clear patterns have emerged: COVID-19 patients describe a sudden and total loss of smell—the light-switch phenomenon. Whereas the congestion that accompanies the common cold might lead to some loss of smell, in COVID-19 cases, congestion is largely absent. And, for the majority of patients, the comeback is equally abrupt. After two to four weeks, the light switch turns back on: smell and taste suddenly return. He pauses. Then there’s a smaller fraction of people—Datta estimates around 20 percent—like me. 

Nearly three months after I’d lost it, my smell very gradually returned, but when it did it had radically altered. Everywhere I went, I perceived the odor of onions. Meanwhile, once-familiar odors now smelled totally different. I had started keeping a list: peanut butter, a former staple, smelled so vile I couldn’t even get myself to open a jar of the stuff. Cigarette smoke, lavender, rosemary, citrus fruit. My mother. Cannabis and coffee smelled indistinguishable to me. 

I felt relieved to discover I wasn’t alone. I began talking to others who had lost their sense of smell and taste from the virus, and in subsequent months had experienced parosmia, or a distorted sense of smell. Scott Shapiro, a fashion stylist from New York, also remembered the abruptness with which he lost his senses. “That morning, I could taste my breakfast,” he recalled over the phone. “At lunch I was like, ‘I literally can’t taste anything.’” 

His symptoms persisted for several weeks, accompanied by just a few days during which he felt a heavy pressure on his chest and shortness of breath. By mid-April, Shapiro said, he’d almost fully recovered his sense of smell. Then, by mid-June, he started to notice that things smelled different. When he attended a Black Lives Matter protest near Washington Square Park, he was struck by the scent. “I noticed there was a really foul rotting-onions smell.” He thought, “Maybe that’s just Manhattan.”

It wasn’t until days later, when the smell of onions became pervasive, that he registered that something was wrong. Others I spoke to recalled similar experiences. The persistent smell of onions. Once-distinct odors smelling indistinguishable from others. For some, the distorted odors were offensive enough to turn them off certain foods and drinks—chocolate, red meat, coriander, red wine, eggs, coffee, cucumbers, tap water, tea. Coca-Cola tasted like rusted metal. Others registered the taste of burned rubber. The list went on.

In fact, the parosmias offer an encouraging clue, Datta tells me. “It’s thought that parosmias relate to the olfactory system regenerating itself,” he says, which requires a basic understanding of how the nose works. In almost every person’s nose, there live millions of sensory neurons. Each of these neurons expresses a single molecule called an odor receptor, of which there are approximately four hundred unique kinds. Think of these receptors as little locks, Datta tells me, while the odors that exist in the environment are the keys. Each time you inhale a scent, odor molecules enter the nose and bind to specific receptors. It’s not a one-to-one match, and any number of these “keys” might effectively fit the lock. In fact, a single odor molecule is capable of binding to several receptors, and it’s that specific pattern of activation that ultimately tells us what the smell is. 

The sensory neurons require a way to deliver that information to the brain—no easy feat, since the nose is separated from the brain by our skull. This task is made possible by the cribriform plate, which is perforated with tiny holes that allow nerves to connect from the sensory neurons to the brain. “So your brain and nose are actually interconnected by these little wires that are traversing holes in your skull,” Datta says. When a lot of sensory neurons are damaged as a result of something like a severe viral illness, both the neurons and their wiring must regenerate. “That wiring has to grow, crawl up the nose through the little holes in your skull, and then land in the olfactory bulb,” he says. There’s not much room for error. Each odor receptor corresponds to a unique location on the olfactory bulb, spanning just a fraction of a millimeter in size. Based on the specific odor receptor that the sensory neuron expresses, it must guide its wiring through the tiny holes in the cribriform plate and find the right spot on the olfactory bulb.

Sometimes, though, and especially in the beginning, they don’t quite nail the landing, causing a kind of mis-wiring that can result in parosmia. Pamela Dalton analogized this malfunction to a switchboard operator who gets the connections mixed up. “She’s taking a call that’s supposed to go to Ms. Johnson and now she’s connecting it to Mr. Jones,” Dalton said. It seemed that in my case, all odors were being misdirected to the smell of onion. (I imagined that my olfactory bulb had even begun to resemble this other bulb.)

Over the past months, Datta and his team of researchers have searched for a coherent explanation for how COVID-19 causes smell loss and that could account for both groups affected: the ones who regain their sense of smell almost as quickly as they lost it, and those who’ve taken the longer path toward recovery, with no clear indication that their sense of smell will ever return to normal. (“We don’t know much about the natural history of COVID, so it is impossible to know yet whether there will be cases of parosmias that are permanent,” Datta said.) Their best guess is that the virus infects not the sensory neurons directly, but rather their support cells, which feed and house them. In most cases, the support cells can recover within a couple of weeks, and because the olfactory sensory neurons haven’t themselves been directly affected, the whole system reboots. The light switch turns back on. However, in a smaller fraction of cases, the damage to the support cells is so severe that the sensory neurons are bereft of support, causing them to die as well. Since the process of regeneration for sensory neurons takes much longer, so, too, does the path toward recovery of smell. 

In the meantime, the psychological fallout from smell loss can be significant. The olfactory bulb resides in the limbic system, the part of the brain that deals with emotion, and loss of smell is a well-recorded risk factor for depression. “Smell, evolutionarily, is a really ancient sense,” Datta says. “And your olfactory system is wired up very directly to centers of your brain involved in memory and emotion.” 

He continues: “Even though we don’t pay that much attention to our sense of smell, as humans we’re constantly engaged subconsciously with the smells in our world, and that gives us a sense of place, and a sense of ongoing emotional well-being. We know where we are, and we subconsciously understand the world around us. And if that is suddenly ripped from you, it’s as if you’re cast adrift.”

As early as March 2020, support groups began to form in response to the widespread sensory loss. A Facebook group called COVID-19 Smell and Taste Loss, started by a United Kingdom–based charity called AbScent, had clocked around ten thousand members by early October. On its Facebook page, members share their stories, ask for advice, and offer tips on dietary alternatives to contend with the unpleasantness of red meat: veggie and black bean burgers, falafel, and tofu.

“I really need some encouragement,” wrote one member in October. “I am steadily sinking into the worst depression and I just don’t know how to come out of it. I don’t know when this will ever end. I don’t know how to live in a world without my senses.” Dozens of others responded with comments expressing their support and solidarity. And there may indeed be hope for us yet: experimental therapies like smell training, where routine exposure to certain smells, most commonly a quartet of essential oils, can retrain the brain to register them. “It gets better,” one user consoled them.

When I finally met the person I’d been talking to all those months, I was struck by how different he looked in person—his face somehow smaller than it appeared on the screen. I felt overwhelmed as I clocked new sensory experiences: the way he moved, the way he felt. My brain scrambled, trying to map the person I knew so intimately onto the novelty of these sensations, relaxing only when he spoke: his voice was the same. The only smell I could discern was the smell of his sweat, which I now perceived as the odor of onions, as I did all sweat. 

In the months that followed, our relationship developed new dimension, complicated by the sensory world and all its stimuli. Since the pandemic began, I often returned to the words of Michael Clune in his essay “Ways of Seeing”: “When you have a conversation with someone without looking at their eyes, real empathy becomes possible. You participate in their words. It’s the closest thing to reading a book.” Now our words, no longer the sole carriers of information, became obscured by other sources; we misunderstood each other more. We sometimes mourned the loss of the former simplicity and its illusion of pureness, though never enough to give up what we had gained: the ability to see and touch each other. 

By late October, the trees have started to turn. On a trip upstate, I can smell the death of leaves, the ambient scent of burning wood. The odor of onions persists, though it’s fainter now.

My smell training consists of doing what I’ve always done: smelling as many things as intently as I can. On walks around my neighborhood, I pass a plant in front of one home and remember to rub its leaves. Lavender, I remind myself as I inhale its oil from my fingertips. On nights after he leaves my apartment, I lift my comforter and slip into bed, burying my face in the place where he lay, searching for his scent. “Him,” I say, hoping that someday I’ll recover what was lost, or else find new ways to remember. 

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