JOHN YANG: According to government data, more than 100 million people in the United States have had COVID.

For most of us, it's meant a few miserable days.

But for about 15 percent of those who have gotten the virus it's meant prolonged symptoms, what's come to be known as long COVID.

More than three years into the pandemic physicians and researchers are still struggling to understand a lot of things about the condition.

Laura Santhanam, our news digital health reporter has written a lot about long COVID.

Laura, one thing they've had trouble with as defining it actually what it is there was a study in the Journal of the American Medical Association recently that tries to stick a step toward definition.

What did they find?

LAURA SANTHANAM: That's exactly right.

So researchers at Mass General Brigham in Boston, they surveyed thousands of long COVID patients and basically asked them through, you know, to tell them, you know, what are your symptoms.

And so what they found were, you know, really echoing a lot of what you hear about from people who've been dealing with long COVID, right?

They took 37 symptoms, whittled them down through infection history and statistical modeling into these 12 symptoms that they say form the hallmark of long COVID, things like brain fog, dizziness, chronic cough, also this thing called post exertional malaise.

So say you, you get up to walk across the room, or you read a recipe to make supper one night, it just wipes you out, things that people used to do that without, you know, even thinking about now, it just -- they're completely exhausted.

And it's just really points to how transformational this disease is.

And also, we're just beginning to understand it.

Researchers call this an attempt to create a common language around how to understand this disease.

JOHN YANG: Is there any correlation between Long COVID and vaccination status?

LAURA SANTHANAM: According to this study, there is evidence that supports that.

So you know, they took these different survey responses from long COVID patients and broke them into four different clusters, looking at types of symptoms, and also severity, you know, people who tended to have the worst symptoms and outcomes and just sort of all of it were those who didn't have their full primary series, so two vaccines, doses of Moderna, or Pfizer, what have you, and also had been infected with COVID, multiple times.

So that combination is really rough for people who are then end up with long COVID.

JOHN YANG: Some COVID experts have reservations about this study, what are their concerns?

LAURA SANTHANAM: You know, it's one of the big concerns about this study is that we're still so early in this process, right?

You know, the researchers themselves, when I asked them, they say, you know, this is not a diagnostic tool.

You don't take this study, and then, you know, diagnose someone one way or another with long COVID.

So what it does do is that it, again, forms a common language around how we can talk about this disease, you know, create clinical trials to then better understand what are the treatments that we should be using for people who are sick with this, and then ultimately working towards creating diagnostic tests, giving someone a test and then saying, do you have this or not?

Another thing that researchers will also tell you, told me, you know, is that, you know, they didn't use lab data to see, you know, if these people did in fact have long COVID.

It's just self-reported survey data, you know, which has its limitations in that respect.

But, you know, another step in this process would be, you know, taking, you know, does they -- do they have an immune response that suggests they have these sorts of disorders.

JOHN YANG: Now, you've talked to in for your reporting on our website, you talked to a lot of people who are experiencing long COVID.

What did they tell you not only about their experiences, their symptoms, but about getting medical care?

LAURA SANTHANAM: Yeah, it's been such a struggle for so many people, and many of them have felt adrift in the healthcare system for some money for as long as, you know, for years.

You know, what, you know, one patient who I talked to said that, you know, if you are lucky enough to find a physician who will listen to you, that's going a long way but so many times they are just sort of round -- it's like a round robin of medical care trying to, you know, create -- find someone who will listen to them, instead of just saying it's all in your head, and then get the kind of care that they need.

A lot of them describe their care as trial and error.

Many of them go to, you know, Facebook groups, they describe the weight for post-COVID care centers as being six months or more the waitlist certainly support those stories.

And it's just really been a struggle for people who again, so many of them struggle to just get up and walk across the room much less, you know, try and get transportation, childcare, their whole life in order so they can get an appointment that takes months in the making.

JOHN YANG: Earlier you mentioned looking for antibodies and some of these people, what else needs to be done?

Or what else is being done to further understand this condition?

And also figure out the best ways to treat it?

LAURA SANTHANAM: That's a really great question.

I mean, you know, that and that's what one of the -- that's one of the things that this study supports is just sort of looking at these 12 symptoms.

How can we treat those symptoms in design clinical studies that are targeting those symptoms.

And then see what happens when we do.

You know, other areas where we need to certainly do more research, or looking at long COVID in pediatric patients in looking at this disease in, you know, pregnant people.

Right.

And those are certainly part of this broader initiative, you know, recover initiative from the National Institutes of Health, which the study is also a part of, but there's certainly a long way to go and long COVID patients have been waiting a very long time to get there.

JOHN YANG: Laura Santhanam, thank you very much.

LAURA SANTHANAM: Thank you.