Two years after the first COVID-19 patients sounded the alarm that symptoms could last for months, it’s clear the phenomenon is widespread – but medical experts still don’t know much about what causes it or how to treat it.
A study by the Centers for Disease Control and Prevention that looked at 353,000 COVID-19 survivors found that about one in four people age 65 or older and one in five adults under 65 will develop a new health condition related to their struggle which could be associated with virus.
However, there isn’t much data on why some people are stuck with symptoms months after most COVID-19 patients recover, or when they might expect to feel better.
Diagnosing what has come to be known as long COVID consists primarily of ruling out anything else that might be causing a patient’s symptoms, said Dr. Thomas Campbell, Professor of Medicine at the University of Colorado School of Medicine and Chief Clinical Research Officer at UCHealth.
The most common reasons patients seek treatment at UCHealth’s long-running COVID clinic are fatigue and respiratory symptoms, such as a persistent cough or shortness of breath — all symptoms that can have many causes, he said.
“It’s not black and white at all,” Campbell said.
It is not unexpected that people who have been ill enough to be treated in an intensive care unit have persistent symptoms, both from the medical condition itself and from the actions needed to save their lives, such as: B. Spending time on a ventilator. Other viruses can also cause persistent symptoms in people who have been mildly ill, but the phenomenon is more common with COVID-19. It’s also unusual to see so many different symptoms.
It still appears that women are more likely to have had COVID for a long time, but it’s possible that this could reflect differences in who seeks care, Campbell said. Data from the UK found the same gender difference, although the American and UK studies disagreed on whether the risk increases with age or peaks between 50 and 69. The UK data did not include people living in care homes, which may have led to an underestimate of how many people over 70 were affected.
For now, treatment still focuses on managing specific symptoms, like giving them medication to reduce their cough and gradually building their strength and endurance through physical therapy, Campbell said. Most patients feel better after three or four months, but people who were less healthy before contracting the virus or who are seriously ill with the virus may take longer, he said.
There’s still a trial-and-error process for medications, but evidence seems to be accumulating of a process in which people’s activity levels are increased extremely slowly, said Dr. Tod Olin, director of the Exercise and Performance Breathing Center at National Jewish Health in Denver. It’s annoying for people used to more strenuous exercise, but overdoing it seems to wipe out much of patients’ progress, he said.
The National Institutes of Health recently launched a study called RECOVER to understand why some people develop COVID symptoms for a long time and others don’t, Campbell said. Individuals who have had COVID-19 and wish to participate can email [email protected].
“In order to effectively treat long COVID, we need to understand it,” he said. “Otherwise it’s just guesswork.”
One cause or several?
Olin said he and his colleagues observed three general types of long COVID patients: those with excessive fatigue and shortness of breath; those whose heart rate increases erratically, causing them to feel dizzy with even minimal activity; and those who have “brain fog”.
There are many other post-COVID symptoms, but these are usually the ones that draw people to seek treatment, he said.
It’s too early to know if these are three manifestations of one disorder or different syndromes with different causes, Olin said.
The CDC researchers looked at 26 disorders affecting the heart, lungs, kidneys, blood vessels, digestive system, brain and muscular system. While the risk of almost all diseases was higher in people with COVID-19, the odds of developing a new respiratory disease were particularly high.
The study did not prove that the virus caused all of these conditions, as it is possible that doctors looked more closely for other problems in patients who had COVID-19, or that some people had a condition before they got the virus and only were diagnosed afterwards.
Some researchers believe long COVID could be caused by a failed immune response, while others believe fragments of the virus could be lurking somewhere in the body, keeping it in a chronic state of inflammation. Some think both might be right, and that some patients might be struggling with yet another underlying problem.
National Jewish researchers also found that in patients who reported excessive fatigue, the cells did not appear to be making good use of the available energy. It’s an intriguing finding, since they typically only see this pattern in people with certain rare diseases, but it’s far too early to say it’s the cause of long-COVID, Olin said.
“It’s a really preliminary signal,” he said.
Vaccinations help – but how much?
A study looking at people treated by the US Department of Veterans Affairs found that those who had been vaccinated and had a breakthrough infection still had an increased risk of several health conditions compared to those who did not have COVID-19.
They were better off than people who weren’t vaccinated before they got sick, with about a 15% reduced risk of post-COVID symptoms – less protection than previous studies suggesting vaccinated people would expect.
Like the CDC effort, the VA study was conducted before omicron took over and before booster shots were widely available, which could affect the results.
dr Zizad Al-Aly, head of research and development for the VA St. Louis Health Care System, said it’s not entirely surprising that vaccinated individuals weren’t fully protected, given the vaccines were designed to prevent serious illness and death. Requiring vaccination to prevent another syndrome is like asking someone who’s trained as a sprinter for years to excel at a marathon, he said.
“They were never designed to protect us from long COVID,” he said.
The benefits were more significant for some conditions. Vaccinated people were about half as likely to develop bleeding disorders as unvaccinated people, and their likelihood of serious lung problems was also significantly lower, Al-Aly said. It’s not entirely clear why the level of protection is different, but it may reflect that vaccinated people are less likely to develop severe COVID-19, which involves lung damage and abnormal clotting, he said.
“It can be a carry-through effect,” he said.
Not everyone is convinced that the benefits are so modest. Other studies have found that vaccination offers better protection against long-lived COVID, with estimates of reducing risk between 50% and 60%, Campbell said. People who receive their care through VA clinics are not the same as the general population, he noted.
“The VA is a patient population that is predominantly male and not necessarily representative,” he said.
There is not yet enough data to know whether reinfections carry the same long-term risk of COVID as an initial battle with the virus, but Al-Aly said he suspects any protection from previous infection would prove modest, if it exists at all. If true, it would pose a major problem, as almost everyone will get infected at some point, he said, and some will get the virus multiple times.
Aside from vaccination, the only way to prevent a long COVID at this point is to not get the virus in the first place. That won’t be a viable plan for most people given that the virus will be with us for the foreseeable future, Al-Aly said.
The country needs a strategy to prevent long-term COVID, whether it’s vaccines specifically designed to prevent those symptoms or treatments that can significantly reduce the chances, he said.
“It’s very difficult to keep avoiding it,” he said.
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