What is long covid? And what is my risk of getting it? : Goats and soft drinks: NPR

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Every week we answer common questions about life during the corona crisis. If you have a question that you would like us to consider for a future post, email us at goatsandsoda@npr.org with subject line: “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 possibility that symptoms may persist after an infection. What is the risk of long-term covid if I become infected? And does it change to be vaccinated?

Over the past year, a wealth of research on long-term covid has been published. Dozens of these studies attempt to estimate the risk of developing persistent symptoms months after a covid infection.

However, a closer look at the data reveals a huge inconsistency: estimates of the prevalence of long covid vary widely, from less than 5% to almost 60% of total covid cases. So what is happening?

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

One of the major problems with this term is “long covid.” What researchers, doctors and the media have called “long covid” is not just a disease or disorder. “It seems that what has been grouped as ‘long covid’ are actually two or three different groups of disorders,” says Pagel.

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

Serious illness puts you at high risk for long-term covid

Many of the early studies focused mainly on people who have been hospitalized with covid. “Obviously, these people will have more serious illnesses,” says geriatrician Dr. Claire Steves at King’s College London. Some people spend time in the intensive care unit or on a ventilator.

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

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

This tissue damage and inflammation can cause a whole host of persistent symptoms, including rapid heartbeat, severe fatigue, breathing problems and cognitive problems.

And organ damage can take a long time to heal, regardless of the cause. In fact, when a person is critically ill in the hospital, the symptoms can linger, say primary care physicians and bioethicists Dr. Zackary Berger at Johns Hopkins University.

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

Studies have shown that for people who are hospitalized with covid, the risk of lingering symptoms six months after covid is quite high, around 50%, says Steves.

Mild or moderate illness can significantly reduce the risk

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

However, many of these studies lack what is called a control group. That is, they do not take into account that these symptoms may be common in people who have not had covid – or who have had other types of infections. In other words, researchers are not sure if these symptoms are linked specifically to covid, or are typical of recovery from many infectious diseases that no one has noticed.

“There is this belief that you have an infectious disease, you get your treatment for it and you are done with it. You go back to work and you feel good,” says Berger. “But for many people, being sick is not the case.”

Take, for example, a bout of pneumonia caused by bacteria. Antibiotics can stop the infection. But then many endure symptoms weeks later. “Half of people have trouble breathing a month after pneumonia,” says Berger. “There are a lot of people, right?

The same goes for the flu. And a study, published in September, this idea clearly shows. Researchers in England analyzed the electronic records of almost 400,000 people with either a confirmed flu or covid diagnosis. Then they looked to see who had any remaining symptoms. Almost 60% of people with covid had at least one symptom that lasted for six months, but almost 40% of people with the flu also had at least one persistent symptom, similar to those seen in people with covid.

“Many people have lingering symptoms after infectious diseases,” says Berger. “I think it’s something we have to realize.”

Another type of “long covid” can thus be people who take longer to recover from an infection, regardless of whether it is influenza, pneumonia or covid. In other words, there may have been “long flu” or “long pneumonia” all along, but it was simply unappreciated.

COVID is probably a new trigger for postviral syndromes

There is growing evidence that SARS-CoV-2 can sometimes trigger several post-viral syndromes, or diseases that are known to occur after an infection. These include one chronic fatigue syndrome, also known as ME / CFSand a blood circulation disorder, called postural orthostatic tachycardia syndrome, or GR├ľKOR.

For example, one study, which included 130 patients in covid hospitals, 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 mild illness can also trigger this illness. “We have a small selection, but in those [patients] in whom the function remains impaired [six months] after covid-19 infection … everyone has met the criteria for ME / CFS “, he wrote in an email to NPR.” I am referring here to patients who have long-term symptoms after mild covid infections, not the hospital group, or those with organ damage after more severe acute covid-19. “

More than 2 million Americans will be affected

So after you have taken into account these other causes of so-called “long covid”, what remains is possibly a disease specific to SARS-CoV-2. “There is no standard definition for this syndrome yet,” says the epidemiologist for infectious diseases Ira Longini at the University of Florida. “It is a collection of symptoms, including shortness of breath, brain fog, fatigue, but also a problem with a particular organ or tissue, such as the heart or brain.”

This disorder may be related to the virus invading an organ or tissue and remaining there, or some lingering inflammation that remains from the body that fights 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 she analyzes indicates that the risk is much lower in people who were not hospitalized in the UK

She says the Office of National Statistics in the UK has the best estimate right now for the prevalence of these long covid symptoms in this population. This data includes self-reports from more than one million people with positive covid diagnoses.

“In general, in the whole population, these data show that the proportion of long-term covid, more than 12 weeks after an infection, is just under 5% of people,” says Steves.

Given the huge number of covid cases in the US (and around the world), even a 5% share means that more than 2 million Americans (and nearly 13 million people globally) will be affected by this specific cluster of covid symptoms for kl. at least several months (and even more will struggle with other postviral problems).

Fortunately, says Steves, the proportion of people who have these persistent covid symptoms decreases drastically one year after infection. “There are definitely individuals who still have symptoms for more than a year, even up to 18 months now,” she says. “But there is a very small proportion of these individuals. Gradually, most get better. I see it in my clinic.”

But because so many people are affected, healthcare professionals must be on the lookout for signs of some type of long-term covid – and keep an open mind about it, says Dr. Paddy Ssentongo, an epidemiologist at Pennsylvania State University. “Doctors have to listen to the patient. They tell what is happening to them. They find no symptoms. Patients know best what is happening to their bodies.”

How to reduce the risk of long-term covid

The best way to reduce the risk of any type of long-term covid is to reduce the risk of having a severe case of covid. And to do that, says Steves, is to be vaccinated at the top of the list. She and her colleagues have it was found that vaccination with two doses reduces the risk by half to get the covid-specific cluster of symptoms after an infection.

But the overall effect of the vaccine on your risk of some form of long-term covid is much greater, says Longini at the University of Florida. “The vaccine reduces the probability of an infection with a disease by maybe 70%. So overall, the reduction in long-term covid among vaccinated people is more than 80 or 90%.

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