Rachel Robles contracted COVID in March 2020. The 27-year-old knowledge analyst has not gone a single day with out signs since. Most medical doctors didn’t imagine her when she described how she had gone from working the Brooklyn Half Marathon the earlier yr to enduring such crippling fatigue that her sofa felt like quicksand. How she all of a sudden struggled to place numbers collectively, regardless of her technical coaching. How regardless of what number of breaths she took, she all the time felt starved for air.

Three months in, one physician advised her, “COVID doesn’t last for 90 days. You either get over it or you die.”

That dichotomy—during which the one attainable outcomes of COVID are both full restoration or dying—has turned out to be something however true. Between 8 million and 23 million Americans are nonetheless sick months or years after being contaminated. The perplexing array of signs generally known as lengthy COVID has left an estimated 1 million of these individuals so disabled they’re unable to work, and people numbers are more likely to develop because the virus continues to evolve and unfold. Some who escaped lengthy COVID the primary time are getting it after their second or third an infection. “It is a huge public health crisis in the wake of acute COVID infection,” says Linda Geng, a doctor and codirector of Stanford Health Care’s lengthy COVID clinic.

Though there isn’t a longer debate that lengthy COVID is an actual phenomenon—each the Centers for Disease Control and Prevention and the World Health Organization have acknowledged its existence—the science is so new that many questions stay about methods to outline the situation, what causes it and methods to successfully deal with it. It has develop into clear, for instance, that lengthy COVID can assume a wide range of completely different kinds. “Not everyone has the same disease,” which implies there are completely different causes, says Akiko Iwasaki, an immunologist on the Yale School of Medicine.

Scientists have proposed a number of completely different, but interconnected, origin tales to clarify these wide-ranging signs: The coronavirus might injury organs, spawn tiny blood clots, set off autoimmunity, conceal out in tissues or immediate new and ongoing signs in different, extra refined methods. To complicate issues additional, these narratives are usually not mutually unique: Several may very well be occurring on the identical time in a selected affected person, or one might set off one other in an sad sequence of occasions that retains the affected person in perpetual dangerous well being. By teasing aside the theories one after the other, researchers are gaining a better understanding of this enigmatic sickness and inching nearer to therapies that don’t simply masks signs however remove the foundation trigger.

Listening to sufferers

Many of the earliest insights into lengthy COVID have been gleaned from the experiences shared by sufferers. A survey by the Patient-Led Research Collaborative, a workforce of lengthy COVID sufferers who’re doing analysis into their situation, compiled an inventory of greater than 200 completely different signs throughout 10 organ programs. These vary from the commonest complaints like fatigue, cognitive impairment, shortness of breath, irregular menstrual durations, complications, coronary heart palpitations, sleep issues, and anxiousness and melancholy, to different afflictions like double imaginative and prescient, peeling pores and skin, hair loss, tinnitus, tremors, meals allergy symptoms, and sexual dysfunction. The constellation of reported signs can differ from individual to individual, even altering over the course of the situation.

Because there isn’t a agreed-upon definition of lengthy COVID, no easy diagnostic check, and no approach to clearly distinguish one subtype from one other, the assorted manifestations of this mysterious situation typically get lumped beneath one huge umbrella, confounding researchers. Yet rising analysis is offering the primary proof for a number of promising hypotheses.

One concept blames the sickness on lingering organ or tissue harm attributable to the preliminary an infection with SARS-CoV-2, the virus behind COVID-19. Though the coronavirus enters the physique via the respiratory tract, it could actually journey via the bloodstream to contaminate the kidneys, coronary heart, nervous system, and intestine. In the method, it could actually set off waves of irritation that reverberate all through the physique, inflicting collateral injury to a number of organs.

In one examine, researchers on the University of Oxford in contrast mind scans of individuals earlier than and after they bought COVID and located that even gentle circumstances may cause the mind to shrink by 0.2 to 2 p.c greater than in individuals who had not been contaminated. Because adults usually lose about 0.2 p.c of their mind quantity in areas associated to reminiscence yearly, that interprets to psychological decline equal to 1 to 10 years of growing older. It’s too quickly to know if this impact is non permanent or would possibly arrange individuals for age-related problems later in life.