How long will it take to understand long COVID? - Ars Technica

Covid long-haulers experience a litany of symptoms, and researchers have proposed a variety of theories to explain them.

The perplexing array of symptoms known as long Covid has left an estimated 1 million of those people so disabled they are unable to work, and those numbers are likely to grow as the virus continues to evolve and spread.

Some who escaped long Covid the first time are getting it after their second or third infection.

“It is a huge public health crisis in the wake of acute Covid infection,” says Linda Geng, a physician and codirector of Stanford Health Care’s long Covid clinic.

Many of the earliest insights into long Covid have been gleaned from the experiences shared by patients.

A survey by the Patient-Led Research Collaborative, a team of long Covid patients who are doing research into their condition, compiled a list of more than 200 different symptoms across 10 organ systems.

A lengthy list of possible symptoms has been amassed from people who are dealing with long Covid.

Many experts believe the persistent health issues following a severe case of Covid are a distinct entity from the assortment of symptoms arising after an asymptomatic or mild infection with the virus, though both may be considered long Covid.

“I think the clearest line in the sand is people who were hospitalized versus people who were not hospitalized,” says David Putrino, a director of rehabilitation innovation for the Mount Sinai Health System, whose team has treated thousands of long Covid patients.

People like Brown who experience organ damage after hospitalization, Putrino says, often benefit from physical rehabilitation, whereas others with long Covid can get worse when they exert themselves.

The majority of long Covid patients — more than 75 percent, according to some estimates — were never hospitalized for their original infection.

Resia Pretorius, a physiologist at Stellenbosch University in South Africa, believes that most long Covid symptoms can be traced back to microscopic blood clots that block tiny vessels and prevent oxygen from reaching the body’s tissues.

Pretorius, who has been analyzing blood plasma samples of Covid patients since the beginning of the pandemic, discovered that in long Covid patients, the microclots that form during acute Covid infection don’t break down the way they should.

It’s no easy business figuring out the causes of the symptoms associated with long Covid.

Others posit that long Covid might arise when the body’s overzealous response to infection knocks the immune response off-kilter, inducing autoimmune disease.

Iwasaki believes that this link between the immune system and long Covid could explain why the illness primarily affects middle-aged women, who are the most vulnerable to autoimmune disorders.

Like some others, she found that some of her symptoms improved after receiving a Covid vaccine, although she still experiences memory lapses and fatigue.

Some long Covid patients may continue to experience symptoms long after their initial infection because they still harbor the coronavirus, in some form, somewhere in their bodies.

If this theory holds true, then vaccines or antivirals could ease long Covid symptoms by helping the body get rid of lingering virus.

A survey of 26,000 people with long Covid by the biotech company 23andMe found that about 20 percent of respondents reported feeling somewhat  better after receiving the Covid vaccine.

Lisa McCorkell, cofounder of the Patient-Led Research Collaborative, says her long Covid symptoms — among them heart palpitations, dizziness, brain fog and fatigue — lessened after she got her shot.

So many people have contracted Covid-19 that the number of people dealing with long Covid is estimated to be very high, as indicated by this 2022 survey.

Similar stories have emerged of long Covid symptoms dissipating after a five-day course of Pfizer’s antiviral drug Paxlovid.

Not only did the patient’s illness resolve quickly, but her long Covid symptoms also went away.

People can accumulate many persistent viruses over the course of a lifetime, according to Proal, and reactivation of one of these during a Covid infection may explain at least some long Covid symptoms

Some evidence suggests that prior infection with Epstein-Barr virus (EBV), which causes mononucleosis, puts people at higher risk for developing long Covid