A Tufts School of Medicine clinical assistant professor and Tufts Medical Center lung specialist on what we know and what we don’t know about lingering symptoms of the virus
At this point in the COVID-19 pandemic, a mild bout of the virus may mean a week or so of symptoms followed by a full recovery. However, a small subset of people infected with the virus never fully recover and experience lingering symptoms and complications. This phenomenon has come to be known as long COVID-19.
According to the Centers for Disease Control and Prevention, approximately 60% of Americans had been infected with COVID-19 as of February 2022, but the number of people getting critically ill or dying from the virus has plummeted, largely due to the wide availability of vaccines.
Tufts Now asked Maher Ghamloush, a lung specialist at Tufts Medical Center and clinical assistant professor at Tufts University School of Medicine, eight pressing questions about long COVID—what defines it, who’s at risk, and what’s next in terms of researching the disease. Here’s what he had to say.
Tufts Now: How long does long COVID last?
Maher Ghamloush: We are still trying to find the answer to that. The closest we've gotten is from a recent study [in the journal Nature] where they followed almost 100,000 Scottish patients who had recovered from an initial bout of COVID-19 for around 18 months. About 5% or 6% of these people have not recovered from long COVID. About 40% of them continue to have partial recovery. So, some people had symptoms even 18 months out.
We have patients in our clinic who have had symptoms since March 2020, so we know it can go beyond two years. Could it be lifelong? It's certainly possible. Could it get better over time? Absolutely. A lot of patients do get better over time.
What are the most common lingering symptoms of long COVID?
The type of symptoms people continue to have can involve any organ system, but most commonly it affects the organs that the acute COVID has a predisposition to attack—the lungs, heart and blood vessels, and possibly the brain. Most of the people we see have a combination of symptoms, which include fatigue, reduced ability to tolerate physical activity, breathing difficulties, cough, as well as difficulty with concentration, memory, and sleep.
There are less common but very impactful symptoms such as headaches, chronic pain, effects on smell and taste, and a fast heart rate. As you can imagine, many of these chronic symptoms can affect someone’s quality of life and their mental health.
If you have symptoms, how do you know if they’re associated with COVID or due to something else?
Think of it not as a single symptom, but a combination of symptoms. Usually people don't only have one, although there are patients who do. For example, I have patients who only have anosmia, or loss of the ability to smell. This is two years after getting COVID and every one of their symptoms has gotten better except this one. In our clinics, we usually perform a workup to exclude other causes.
Studies that have looked at large populations have also identified an uptick in the risk of deep vein thrombosis—as much as two to three times the risk in the general population. Some people will develop deep vein thrombosis whether they had COVID or not. Can we tell you for sure if it's connected to long COVID if it's a single symptom or a single complication in an individual? Probably not. But in large epidemiologic studies, we can find strong associations.
We've always had patients presenting to our clinic with long-term effects of viral infections and we never labeled it a disease. We just say, “plus infectious complications.” The silver lining [of the COVID-19 pandemic] is that we can now study these long-term infectious complications as a separate disease.
Can you talk about some of the emotional effects you’ve seen in people with long COVID?
It is very anxiety-provoking to have these symptoms that can come on at any time. You feel good for a while, and then all of a sudden you feel very tired and fatigued and can't do anything, which makes it very difficult to plan your life.
People who’ve had issues with anxiety or depression might be predisposed to a worsening of these symptoms with long COVID, but even people who may have never had any mental health issues can develop them. You're bombarded with medical stressors that can certainly increase anxiety and depression, because long COVID may cause memory and concentration issues, which can be very frustrating.
Working with people's coping skills is a large part of what I do. It’s not just about trying to figure out where and what the problem is, but how do we cope with it?
What about the brain fog some people report?
At this point, it's still a clinical evaluation and there’s a subjective aspect to it. We can put people through a battery of tests and ask them to do specific tasks that require a higher level of executive functioning. It tests their memory and their ability to concentrate, as well as their ability to problem solve and come up with a solution.
This brain fog is partly interfering, I believe, with their ability to function. If they have brain fog, they're not going to go out and exercise. They're not going to go out and try to recover from other issues related to long COVID.
Are some people at higher risk for long COVID, or genetically predisposed?
We haven't identified all the risk factors, but we know that older age is certainly a factor. We also know that females are more predisposed to getting long COVID than males.
Obviously having other comorbid illnesses is also a risk factor. So, if you have chronic kidney disease, you're more likely to develop worsening kidney function after developing COVID.
We've had patients who have barely felt any symptoms and then a couple weeks later start developing symptoms and they haven't recovered since—and these are younger patients who are physically active and continue to suffer a year or two down the road from this. There's probably some genetic predisposition. Clearly some of us have a more robust immune response to infections than others.
Is there any way to prevent long COVID?
The best way to decrease your risk of long COVID seems to be vaccination. It's not 100% protective because we know there are people who are vaccinated who still develop long COVID, but it definitely reduces your risk.
A recent study finding that taking Paxlovid, an antiviral medication, reduces the chances of getting long COVID supports the hypothesis that by reducing the severity of acute COVID by suppressing viral replication, we are not only able to reduce hospitalization and death in the short-term, but limit long-term consequences.
A major finding of the study is that only 16% of the at-risk group took Paxlovid, which tells us that the health-care community and policymakers should put more effort into making the medication acceptable and accessible to at-risk populations. There have been recent studies that have suggested that regular physical activity may reduce the risk of severe COVID-19, and we know that developing severe disease is a risk factor for long COVID.
So, what you can do today is what doctors always recommend: eat healthy foods and get regular exercise.
What is your research on long COVID focused on now?
We are doing a study where we're enrolling patients who've had COVID and have had continued symptoms or new symptoms, including breathing issues, inability to exercise, or chronic fatigue three months out.
We’re trying to see if there are blood biomarkers, which are proteins in the blood that can potentially be increased or decreased in people who have chronic issues after COVID, including chronic inflammation or chronic pathologic healing. We think that some of the problem with long COVID is that possibly the blood vessels aren't healing as well as they should. So, we're looking at this list of proteins trying to see if we can find any specific pattern.
I think we’ll eventually find that there are different types of long COVID. The complications are very variable and the treatments in the future will be very variable depending on what specific combination of symptoms or processes we can identify that caused long COVID.
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