What is long COVID? And what is my risk of getting it? : Goats and Soda: NPR


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Every week, we answer frequently asked questions about life during the coronavirus crisis. If you have a question that you would like us to consider for a future post, email us at goatsandsoda@npr.org with the theme: “Weekly Coronavirus Questions.” See an archive of our Frequently Asked Questions here.

One of the most frightening aspects of COVID-19 now seems to be the potential that symptoms could remain after infection. What is my risk of having a long COVID if I become infected? And does vaccination change that?

Over the past year, there has been a lot of research published on long COVID. Dozens of these studies attempt to assess the risk of having persistent symptoms months after COVID infection.

But when you look closely at the data, a huge discrepancy emerges: Estimates of the prevalence of long-term COVID vary wildly, from less than 5% to nearly 60% of total COVID cases. So what’s going on?

“It can be really confusing, even for scientists,” says Christina Pagel, who heads the Clinical Surgery Research Unit at University College London.

One of the main problems is with this term “long COVID”. What scientists, doctors and the media have called “long COVID” is not just one disease or illness. “It looks like what was grouped as‘ long COVID ’, there are actually two or three different groups of disorders,” says Pagel.

Each of these disorders can have a separate set of symptoms and causes. Some affect populations differently than others, or remain for a different period of time.

Severe illness puts you at high risk of long COVID

Many of the early studies focused primarily on people who were hospitalized with COVID. “Obviously, these people will have more severe illnesses,” says geriatric doctor Claire Steves at King’s College London. Some people spend time in the ICU or on a fan.

With this severe disease comes a high risk of organ damage, either due to the virus itself or due to the body’s response to fight it. “Some people may have respiratory scars and a kind of fibrosis that comes from inflammation in the lungs,” she says.

Some people have inflammation in their heart muscle, called myocarditis. Some have inflammation in their blood vessels or their brains. “In some individuals, there are certain signs of changes in the areas of the brain that are sensitive to odor,” Steves says.

This tissue damage and inflammation can cause many persistent symptoms, including rapid heart rate, severe fatigue, respiratory problems, and cognitive problems.

And organ damage can take a long time to heal, no matter the cause of it. In fact, whenever a person is seriously ill in the hospital, symptoms can remain, says primary care physician and bioethicist Dr. Zackary Berger at Johns Hopkins University.

“It’s well known that people need a long time to recover from a critical illness,” Berger says. “So I think it’s not surprising that people who end up in the ICU would take longer to recover.”

Studies have found that for people hospitalized with COVID, the risk of persistent symptoms six months after COVID is quite high, about 50%, Steves says.

Mild or moderate illness can considerably reduce the risk

Many news reports have suggested that the risk of getting long-term COVID after a mild or moderate infection seems similar to the risk after a severe case. Indeed, some studies have found that up to 60% of people report one or more persistent symptoms six months after catching SARS-CoV-2, including fatigue, brain fog, difficulty breathing, chest pain, coughing, joint and muscle pain, abdominal symptoms. , headaches and anxiety or depression.

But many of these studies lack what is known as a control group. That is, they do not consider that these symptoms may be common in people who have not had COVID – or who have had other types of infections. In other words, scientists are not sure whether these symptoms are linked specifically to COVID, or are typical for a cure for many infectious diseases that no one has noticed.

“It’s this belief that you have an infectious disease, you get your treatment for it and you’re done with it. You go back to work and you’re fine,” Berger says. “But for a lot of people, being sick isn’t like that.”

Take, for example, an attack of pneumonia caused by bacteria. Antibiotics can stop the infection. But then many people endure symptoms weeks later. “Half of people have trouble breathing a month after pneumonia,” Berger says. “That’s a lot of people, isn’t it?

The same goes for the flu. And a study, published in September, demonstrates this idea clearly. Researchers in England have analyzed the electronic health records of nearly 400,000 people with either a confirmed flu or a COVID diagnosis. Then they looked to see who had prolonged symptoms. Nearly 60% of people with COVID had at least one symptom lasting six months, but nearly 40% of people with influenza also had at least one persistent symptom, similar to those seen in people with COVID.

“A lot of people have persistent symptoms after infectious diseases,” Berger says. “I think that’s something we need to accomplish.”

Thus, another type of “long COVID” may be people who take longer to recover after an infection, whether it is the flu, pneumonia, or COVID. In other words, there may have been a “long flu,” or “long pneumonia,” all the time, but it was simply unappreciated.

COVID is likely to be a new trigger for post-viral syndromes

There is growing evidence that SARS-CoV-2 can sometimes trigger several post-viral syndromes or diseases known to occur after infection. These include chronic fatigue syndrome, also called ME / CFS, and blood circulation, called postural orthostatic tachycardia syndrome or POTS.

For example, one study, which included 130 patients hospitalized with COVID, found that 13% of them met the criteria for ME / CFS six months after their diagnosis.

Dr. Peter Rowe at Johns Hopkins University has evidence that a mild illness can also trigger this disease. “We have a small sample size, but in those [patients] in which function remains impaired [six months] after COVID-19 infection … all met criteria for ME / CFS, ”he wrote in an email to NPR.“ I am referring here to the patients who have prolonged symptoms after mild COVID infections, not the hospitalized group, or those. with organ damage after more severe acute COVID-19. “

More than 2 million Americans will be affected

So after you consider these other causes of so-called “long COVID,” what remains may be a disorder that is specific to SARS-CoV-2. “There is still no standard definition for this syndrome,” says infectious disease epidemiologist Ira Longini at the University of Florida. “It’s a collection of symptoms, including shortness of breath, brain fog, fatigue, but also a problem with one particular organ or tissue, such as the heart or brain.”

This disorder could be linked to the virus that invades an organ or tissue and persists there, or to some ongoing inflammation left behind by the body fighting the virus, Longini says.

It is not yet known exactly what percentage of people will have this collection of symptoms months after COVID, but Steves at King’s College London says her analysis indicates the risk is much lower in people who have not been hospitalized in the UK.

She says the Office for National Statistics in the UK has the best assessment, right now, of the prevalence of these long-term COVID symptoms in this population. These data include self-reporting of more than a million people with positive COVID diagnoses.

“Overall, in the overall population, these data show that the rate of long-term COVID, more than 12 weeks after infection, is just under 5% of people,” says Steves.

Considering the enormous number of COVID cases in the United States (and around the world), even a 5% rate means that more than 2 million Americans (and nearly 13 million people worldwide) will be affected by this specific set of COVID- symptoms for at. at least a few months (and will struggle even more with other post-virus problems).

Fortunately, says Steves, the percentage of people who have these persistent COVID symptoms decreases dramatically a year after infection. “There are certainly individuals who still have symptoms for more than a year, even up to 18 months now,” she says. “But there’s a very small percentage of those individuals. Gradually most people get better. I see that in my clinic.”

However, because so many people are affected, health care workers need to pay attention to signs of any type of long-term COVID – and keep an open mind about it, says Dr. Paddy Ssentongo, an epidemiologist at Pennsylvania State University. “Doctors need to listen to the patient. They tell you what’s happening to them. They’re not making symptoms. Patients know best what is happening to their bodies.”

How to reduce your risk of long COVID

The best way to reduce your risk of any long COVID is to reduce your risk of getting a severe case of COVID. And to do that, Steves says, being vaccinated is at the top of the list. She and her colleagues found that vaccinated with two doses halved the risk of having the COVID-specific set of symptoms after infection.

But the overall impact of the vaccine on your risk of any long-term COVID is much greater, says Longini at the University of Florida. “The vaccine reduces the probability of infection with disease by perhaps 70%. So overall, the reduction in long-term COVID among vaccinated people is more like 80 or 90%.

“That just shows you the power of the COVID-19 vaccines,” he adds. They protect not only against acute disease, but also against the various types of chronic diseases associated with SARS-CoV-2.

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