What Do We Know About Long COVID?

What is long COVID? What are its symptoms? Can it be treated? Is it dangerous? Researchers have some answers, but it remains one of the pandemic’s great mysteries.

Three years in, scientists still aren’t quite sure why some people get stuck with the syndrome and its cluster of debilitating symptoms long after their COVID-19 infection has cleared, while others breeze through and quickly return to a normal life.

In part, that’s because long COVID is so hard to pin down. For some patients, the main symptom is fatigue; for others, heart and respiratory problems. Still others may have frequent headaches, trouble sleeping, loss of taste, stomach pain, rash, muscle aches, or changes in menstrual cycles—or maybe a mix of symptoms. One patient may have a few annoying complaints for a couple of weeks, a second seemingly permanent discomfort.

There’s no simple formula for diagnosing patients, no test to tie symptoms to COVID-19, no pill to pop to make everything go away. Scientists and the public can’t even agree on what to call it: take your pick from long COVID, post-COVID conditions, long-haul COVID, post-acute COVID-19, post-acute sequelae of SARS CoV-2 infection, and chronic COVID.

Because it’s so difficult to diagnose, it’s also tough to figure out how many people have had it, but the Centers for Disease Control and Prevention suggests about 15% of all Americans have suffered from long COVID and that about 6% currently have it.

At the Boston University Chobanian & Avedisian School of Medicine and its primary teaching hospital, Boston Medical Center (BMC), researchers and clinicians are trying to decode long COVID.

As well as treating patients through the ReCOVer Long COVID Clinic, they’re leading the National Institutes of Health-funded RECOVER (Research COVID to Enhance Recovery) Long COVID Study, an effort to better understand the condition and pioneer new prevention and treatment approaches.

Here, Jai G. Marathe, assistant professor of medicine at Boston University and Boston Medical Center infectious diseases physician, and Fitzgerald Shepherd, assistant professor of general internal medicine and Boston Medical Center hospitalist, break down what they’ve learned about long COVID since starting the study last year:

Q: What do we know today about long COVID that we didn’t know a year ago?

A: Marathe: That a lot of people recover; it’s a matter of time. But we also have people who have had persistent symptoms since the beginning of the pandemic. It’s a whole mishmash of timelines, depending on where they are in their trajectory for recovery versus plateauing with their symptoms.

Q: On the flip side, what don’t you know; what are you still trying to figure out?

A: Shepherd: We’re trying to decipher the long-term effects. Right now, the study is going into year two—we’re trying to see if the effects that we know are in the medium term persist over the long term, and what the duration is likely to be, whether it’s something that will be permanently there, or if it will resolve in time.

Q: How many patients are you working with in the long COVID clinic?

A: Marathe: We have already evaluated and seen more than 350 patients in the one year that we’ve been active and we continue to receive a fair number of referrals every month. We have a waiting list, unfortunately, similar to others in our area.

The reality with long COVID is that we don’t have a treatment that universally applies to everybody and that can result in a cure. Because we don’t understand why some people develop long COVID, and why it persists, we continue to provide individualized care plans with the hope of getting the patients through their journey toward a plan to recovery.

Q: Although there’s a real mishmash of recovery timelines, are there common long COVID symptoms?

A: Marathe: The most common symptom that we see in the clinic is post-exertional fatigue. Minimal exertion, like talking for an hour, will cause profound exhaustion for the patient, let alone doing their groceries. The second most common is memory fog. We see a lot of patients with autonomic dysfunction, where they have dizziness, palpitations, a combination of symptoms, and a fair number of patients complain of GI symptoms like nausea, vomiting, diarrhea that have either worsened or are new since their diagnosis of COVID-19.

Q: You touched on this a little, but just how long is long COVID for most people? Is there an average, or is it really all over the place?

A: Shepherd: It’s very varied, especially for different patients, and we don’t have a way to really identify who will have it, or for how long. “Long” is an arbitrary term.

Q: Do particular groups of people seem to be more at risk, as with COVID-19?

A: Marathe: People who had severe COVID-19 disease are more likely to have long COVID. So, if you were hospitalized or in the ICU because of your original COVID-19 infection, you’re more likely to have long COVID. Similarly, older age and multiple medical problems can lead to longer duration of symptoms after a COVID-19 recovery.

We haven’t noticed it so much in our clinic, but what is reported in literature is that women and people who belong to the transgender community are disproportionately impacted by the symptoms of long COVID.

What is underreported is racial and ethnic disparities in the development of long COVID. Over the last 6 months, all of the races and ethnicities have hovered around 10% of patients who are reporting symptoms. But I always worry about the disparities, because whether it is underrecognized in specific communities because of lack of knowledge, whether care is accessible to them or not, might be impacting who we are seeing in our clinics.

Q: Is it hard to diagnose long COVID given the wide range of symptoms that you see?

A: Marathe: The definition of long COVID is really broad, so it encompasses anybody who has new or worsening symptoms after their diagnosis of COVID-19. We see a lot of mood disorders; a lot of anxiety and depression. For people who had preexisting symptoms and now come to the clinic and say it’s worse after COVID-19, we would still diagnose them with long COVID, but it’s hard to tease out what is progression of that preexisting disease process. If someone has diabetes and they say their control is worse after COVID-19, would it be a natural progression of their disease process, or is it truly related to the COVID-19 disease they experienced? That’s where the challenges come into play.

There is no one-pill-fits-all situation for treatment of long COVID. If you are treating somebody for diabetes or hypertension, it [their treatment] wouldn’t necessarily change. We support them. We say, “Maybe this is long COVID, but we still need to treat you this way.”

Q: What stage is the RECOVER study in now, and what are your next steps?

A: Shepherd: We have completed our enrollment—we’ve enrolled 107 participants, most of whom have had COVID; we also have some negative controls. We are trying to retain the patients as we monitor them on a three-month basis to evaluate the progression of their disease and how it evolves with time. The aim is to have a prospective view over four years in total.

Q: And at the moment, the only proven way to avoid long COVID is to…

A: Shepherd: …not get COVID.

Q: But there has been some positive news about medicines that could prevent and treat it. How far away are effective therapeutics?

A: Marathe: We are going to be a site for a long COVID treatment program called RECOVER Vitals to look at Paxlovid being used for treatment of long COVID. It is in the early stages of roll out, but we expect that it will be rapidly ramped up and provide us with more answers. There are other components to this big study, so the samples can be used with patient participant permission to look at why some people are prone to developing long COVID, and whether there are newer modalities to intervene for prevention or for treatment.

Q: You must get a lot of people coming to you with fears about long COVID. What do you say to reassure them about what can be done now?

A: Marathe: Because long COVID was a patient-coined term, it’s quite ambiguous. Some of my patients ask, “Am I going to die with long COVID?” Deaths have certainly been recorded, but not at our location—we haven’t had any deaths from long COVID at BMC.

I think the key thing for patients and your readers to take away is: If you are struggling with symptoms, you have to be patient; it’s a matter of time that your body overcomes a lot of the symptoms that you’re experiencing today. Full recovery happens—it’s gradual.

A lot of our patients have had full recovery, and we’ve been able to successfully discharge them. For some who have had a slower recovery, having community support around them, and feeling heard as opposed to being invisible—because some of these symptoms are hard to explain—is really important to maintaining a positive outlook on outcomes.

Being able to advocate for yourself and engage with the medical community, which a lot of our patients are truly hesitant about doing, is very important as well.

If anybody experiences challenges, then reaching out to long COVID clinics for additional help would be the next step and recognizing that we are here for our patients.

Q: Has working with long COVID patients shaped your own coronavirus prevention strategies?

A: Shepherd: I do mostly inpatient, but we still advocate to patients—even for the patients that we are sending from the inpatient to the outpatient setting—that wearing a mask is protective, both for yourself and those around you, even though it’s no longer a federal or state mandate. It is still practiced within the hospital settings. We still do wear masks during our day-to-day within BMC. We’re still spreading that message that for personal safety it’s recommended.

Marathe: The key to not having long COVID is to never get COVID in the first place, and to do that, masking as well as vaccination—being up-to-date on vaccines—is important. If you do develop COVID-19, you test positive, notify your health care provider, because there’s treatments for COVID-19 if you are at risk. It’s preliminary, but there is some data that suggests use of Paxlovid for acute infection may decrease the progression to long COVID. If that holds true, then getting early treatment would also be helpful in preventing the disease.