During the first few months of the coronavirus pandemic, the United States became a nation of novice hermits and amateur epidemiologists. The former battened down the hatches; the latter frantically tried to assess just how much danger we were hiding from. Between sourdough seminars and Zoom meetings, Twitter PhD theses were composed and defended seeking to pin down the “infection fatality rate”: the percentage of infected people, including the undiagnosed, who died of covid-19.

In those early innings, good-faith estimates ranged as high as 3 percent and as low as 0.1 percent. As we got more information, however, the plausible estimates narrowed, and is probably in the range of 0.5 to 1.0 percent.

But with more data, something else has become clear: We’re focusing too much on fatality rates and not enough on the people who don’t die but don’t entirely recover, either.

Ajeet Vinayak of Georgetown University Hospital breaks down how covid-19 attacks the lungs of patients, leaving possible long-lasting damage. (John Farrell/The Washington Post)

Anecdotal reports of these people abound. At least seven elite college athletes have developed myocarditis, an inflammation of the heart muscle that can have severe consequences, including sudden death. An Austrian doctor who treats scuba divers reported that six patients, who had only mild covid-19 infections, seem to have significant and permanent lung damage. Social media communities sprang up of people who are still suffering, months after they were infected, with everything from chronic fatigue and “brain fog” to chest pain and recurrent fevers.

Now, data is coming in behind the anecdotes, and while it’s preliminary, it’s also “concerning,” says Clyde Yancy, chief of cardiology at Northwestern University’s Feinberg School of Medicine. A recent study from Germany followed up with 100 recovered patients, two-thirds of whom were never sick enough to be hospitalized. Seventy-eight showed signs of cardiac involvement, and MRIs indicated that 60 of them had ongoing cardiac inflammation, even though it had been at least two months since their diagnosis.

If these results turned out to be representative, they would utterly change the way we think about covid-19: not as a disease that kills a tiny percentage of patients, mostly the elderly or the obese, the hypertensive or diabetic, but one that attacks the heart in most of the people who get it, even if they don’t feel very sick. And maybe their lungs, kidneys or brains, too.

It’s too early to say what the long-term prognosis of those attacks would be; with other viruses that infect the heart, most acute, symptomatic myocarditis cases eventually resolve without long-term clinical complications. Though Leslie Cooper, a cardiologist at the Mayo Clinic, estimates that 20 to 30 percent of patients who experience acute viral myocarditis end up with some sort of long-term heart disease including recurrent chest pain or shortness of breath, which can be progressive and debilitating. When I asked whether the risk of long-term disability from covid-19 could potentially end up being greater than the risk of death, Cooper said: “Yes, absolutely.”

Those patients would, on average, be much younger than the ones who are dying; the median age in the German study was 49. These are patients with many years of life to lose, either to disability or early death. And there are disturbing findings from much younger patients; a study of 186 children who had MIS-C, the (thankfully rare) inflammatory syndrome that can occur with pediatric covid-19, showed 15 had developed aneurysms of the coronary artery.

But you can’t generalize from such small studies, especially since covid-19 is rapidly becoming the most-studied disease in human history; if we regularly put patients with other viral infections through cardiac MRIs, what might their hearts look like a few months in?

We desperately need larger, more comprehensive studies, and, thankfully, they’re in the works — one of the largest and the best will follow 10,000 British patients. But these take time to set up, and as genetic epidemiologist Louise Wain, a researcher on the British study, told me ruefully, “No one warned us a year ago that we were going to have a pandemic.” She hopes to have the 1,000th patient enrolled by September, which is amazingly fast, but still not quick enough for policymakers and individuals who have to decide whether to leave our hermitages.

“All of us, me included, have tired,” says Yancy. And, in recent months, our laser focus on fatality rates has offered at least the young and healthy what seems like a beacon of hope. Without hard data, it has been easy to dismiss reports of longer-term complications as anecdote, hysteria or media hype. But at this stage, the absence of data isn’t proof that those effects aren’t real.

Of course, even if the risks are higher than we thought, we still must make trade-offs — crops must be picked and kids educated, pandemic or no. But whatever your personal cost-benefit analysis was, it should become more conservative with those potential long-term complications factored in. At the very least, says Yancy, “Wear the mask. When you think about all these ramifications, wear the mask.”

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