Photo: Dr. F.A. Murphy/Getty Images/Visuals Unlimited

You call a friend and arrange to meet for lunch. It’s unseasonably springlike, so you choose a place with outdoor seating, which seems like it should be safer. As usual, you take all reasonable precautions: You use hand sanitizer, sit a good distance from other customers, and try to avoid touching your face, though that last part is hard. A part of you suspects that this whole thing might be overblown.

What you don’t know is that ten days ago, your friend’s father was a guest of his business partner at the University Club, where he caught the novel coronavirus from the wife of a cryptocurrency speculator. Three days after that, he coughed into his hand before opening the door of his apartment to welcome his son home. The saliva of COVID-19 patients can harbor half a trillion virus particles per teaspoon, and a cough aerosolizes it into a diffuse mist. As your friend walked through the door he took a breath and 32,456 virus particles settled onto the lining of his mouth and throat.

Viruses have been multiplying inside his body ever since. And as he talks, the passage of his breath over the moist lining of his upper throat creates tiny droplets of virus-laden mucus that waft invisibly into the air over your table. Some settle on the as-yet-uneaten food on your plate, some drift onto your fingers, others are drawn into your nasal sinus or settle into your throat. By the time you extend your hand to shake good-bye, your body is carrying 43,654 virus particles. By the time you’re done shaking hands, that number is up to 312,405.

One of the droplets gets drawn into the branching passages of your lungs and settles on the warm, wet surface, depositing virus particles into the mucus coating the tissue. Each particle is round and very small; if you magnified a human hair so that it was as wide as a football field, the virus particle would be four inches across. The outer membrane of the virus consists of an oily layer embedded with jagged protein molecules called spike proteins. These stick out like the protrusions on a knobby ball chew toy. In the middle of the virus particle is a coiled strand of RNA, the virus’s genetic material. The payload.

As the virus drifts through the lung’s mucus, it bumps into one of the cells that line the surface. The cell is considerably larger than the virus; on the football-field scale, it’s 26 feet across. A billion years of evolution have equipped it to resist attackers. But it also has a vulnerability — a backdoor. Protruding from its surface is a chunk of protein called angiotensin converting enzyme 2, or ACE2 receptor. Normally, this molecule plays a role in modulating hormone activity within the body. Today, it’s going to serve as an anchor for the coronavirus.

As the spike protein bumps up against the surface of the lung cell, its shape matches that of the ACE2 so closely that it sticks to it like adhesive. The membrane of the virus then fuses with the membrane of the cell, spilling the RNA contents into the interior of the lung cell. The virus is in.

The viral RNA gets busy. The cell has its own genetic material, DNA, that produces copied fragments of itself in RNA form. These are continuously copied and sent into the main body of the cell, where they provide instructions for how to make the proteins that carry out all the functions of the cell. It’s like Santa’s workshop, where the elves, dutifully hammering out the toys on Santa’s instructions, are complexes of RNA and protein called ribosomes.

As soon as the viral RNA encounters a ribosome, that ribosome begins reading it and building viral proteins. These proteins then help the viral RNA to copy itself, and these copies then hijack more of the cell’s ribosomes. Other viral proteins block the cell from fighting back. Soon the cell’s normal business is completely overwhelmed by the demands of the viral RNA, as its energy and machinery are occupied with building the components of countless replica viruses.

As they are churned out, these components are transferred on a kind of cellular conveyor belt toward the surface of the cell. The virus membrane and spike proteins wrap around RNA strands, and a new particle is ready. These collect in internal bubbles, called vesicles, that move to the surface, burst open, and release new virus particles into your body by the tens and hundreds of thousands.

Meanwhile, spike proteins that haven’t been incorporated into new viruses embed themselves directly into the host cell’s membrane so that it latches onto the surface of an adjacent cell, like a pirate ship lashing itself to a helpless merchantman. The two cells then fuse, and a whole host of viral RNA swarms over into the new host cell.

All up and down your lungs, throat, and mouth, the scene is repeated over and over as cell after cell is penetrated and hijacked. Assuming the virus behaves like its relative, SARS, each generation of infection takes about a day and can multiply the virus a millionfold. The replicated viruses spill out into the mucus, invade the bloodstream, and pour through the digestive system.

You don’t feel any of this. In fact, you still feel totally fine. If you have any complaint at all, it’s boredom. You’ve been a dutiful citizen, staying at home to practice social distancing, and after two days of bingeing on the Fast & Furious franchise, you decide that your mental health is at risk if you don’t get outside.

You call up an ex, and she agrees to meet you for a walk along the river. You’re hoping that the end-of-the-world zeitgeist might kindle some afternoon recklessness, but the face mask she’s wearing kills the vibe. Also she tells you that she’s decided to move in with a guy she met at Landmark. You didn’t even know she was into Landmark. She gives you a warm hug as you say good-bye, and you tell her it was great to see her, but you leave feeling deflated. What she doesn’t know is that an hour before, you went to the bathroom and neglected to wash your hands afterward. The invisible fecal smear you leave on the arm of her jacket contains 893,405 virus particles. Forty-seven seconds after she gets home, she’ll hang up her coat and then scratch an itch at the base of her nose just before she washes her hands. In that moment, 9,404 viral particles will transfer to her face. In five days, an ambulance will take her to Mount Sinai.

Like a retail chain gobbled up by private equity, stripped for parts, and left to die, your infected cells spew out virus particles until they burn themselves out and expire. As fragments of disintegrated cells spread through your bloodstream, your immune system finally senses that something is wrong. White blood cells detect the fragments of dead cells and release chemicals called cytokines that serve as an alarm signal, activating other parts of the immune system to swing into action. When responding immune cells identify a cell that has become infected, they attack and destroy it. Within your body, a microscopic Battle of the Somme is raging with your immune system leveling its Big Berthas on both the enemy trenches and its own troops. As the carnage mounts, the body’s temperature rises and the infected area becomes inflamed.

Two days later, sitting down to lunch, you realize that the thought of eating makes you feel nauseated. You lie down and sleep for a few hours. When you wake up, you realize that you’ve only gotten worse. Your chest feels tight, and you’ve got a dry cough that just won’t quit. You wonder: Is this what it feels like? You rummage through your medicine cabinet in vain and ultimately find a thermometer in the back of your linen closet. You hold it under your tongue for a minute and then read the result: 102. Fuck, you think, and crawl back into bed. You tell yourself that it might just be the regular flu, and even if worse comes to worst, you’re young(-ish) and otherwise healthy. You’re not in the high-risk group.

You’re right, of course, in a sense. For most people infected with the coronavirus, that’s as far as it goes. With bed rest, they get better. But for reasons scientists don’t understand, about 20 percent of people get severely ill. Despite your relative youth, you’re one of them.

After four days of raging fever and feeling sore all over, you realize that you’re sicker than you’ve ever been in your life. You’ve got a dry cough that shakes you so hard that your back hurts. Fighting for breath, you order an Uber and head to the nearest emergency room. (You leave 376,345,090 virus particles smeared on various surfaces of the car and another 323,443,865 floating in aerosols in the air.)

At the ER, you’re examined and sent to an isolation ward. As doctors wait for the results of a test for the coronavirus, they administer a CT scan of your lungs, which reveals tell-tale “ground-glass opacities,” fuzzy spots caused by fluid accumulating where the immune-system battle is the most intense. Not only have you got COVID-19, but it’s led to a kind of intense and dangerous pneumonia called acute-respiratory-distress syndrome, or ARDS.

With all the regular beds already occupied by the many COVID-19 sufferers, you’re given a cot in a room alongside five other patients. Doctors put you on an intravenous drip to supply your body with nutrients and fluids as well as antiviral medicine. Within a day of your arrival, your condition deteriorates. You throw up for several days and start to hallucinate. Your heart rate slows to 50 beats a minute. When a patient in the next room dies, doctors take the ventilator he was using and put you on it. By the time the nurse threads the endotracheal tube down your throat, you’re only half-conscious of the sensation of it snaking deeper and deeper toward your lungs. You just lie there as she places tape over your mouth to keep the tube in place.

You’re crashing. Your immune system has flung itself into a “cytokine storm” — an overdrive of such intensity that it is no longer fighting just the viral infection but the body’s own cells as well. White blood cells storm your lungs, destroying tissue. Fluid fills the tiny alveolar sacs that normally let the blood absorb oxygen. Effectively, you’re drowning, even with the ventilator pumping oxygen-enriched air into your lungs.

That’s not the worst of it. The intensity of the immune response is such that under its onslaught, organs throughout the body are shutting down, a process known as multiple-organ-dysfunction syndrome, or MODS. When your liver fails, it is unable to process toxins out of your blood, so your doctors rush to hook you up to a round-the-clock dialysis machine. Starved of oxygen, your brain cells begin to expire.

You’re fluttering on the edge between life and death. Now that you’ve slipped into MODS, your odds are 50-50 or worse. Owing to the fact that the pandemic has stretched the hospital’s resources past the breaking point, your outlook is even bleaker.

Lying on your cot, you half-hear as the doctors hook you up to an extracorporeal-membrane-oxygenation (ECMO) machine. This will take over the work of your heart and lungs and hopefully keep you alive until your body can find its way back to equilibrium.

And then, you are flooded with an overwhelming sense of calm. You sense that you have reached the nadir of your struggle. The worst of the danger is over. With the viral attack beaten, your body’s immune system will pull back, and you’ll begin the slow, painstaking journey to full recovery. Some weeks from now, the doctors will remove the tube from your throat and wheel away the ventilator. Your appetite will come back, and the color will return to your cheeks, and on a summer morning you’ll step out into the fresh air and hail a cab for home. And later still, you’ll meet the girl who will become your wife, and you’ll have three children, two of whom will have children of their own, who will visit you in your nursing home outside Tampa.

That’s what your mind is telling itself, anyway, as the last cells of your cerebral cortex burst in starburst waves, like the glowing algae in a midnight lagoon. In the isolation ward, your EKG goes to a steady tone. The doctors take away the ventilator and give it to a patient who arrived this morning. In the official records of the COVID-19 pandemic, you’ll be recorded as victim No. 592.

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