Of the nearly half a billion people who have contracted COVID globally so far, an estimated 10-50% will experience long-term symptoms. For four weeks to years after the initial diagnosis, the scars of the virus can linger, affecting how patients go about their daily lives.
Medical experts are still trying to figure out why the long COVID grips some patients and not others. According to a study in the journal Cell, a patient may be more prone to long-term symptoms if they have one or more of the following biological factors: high viral load at initial infection, flood of autoantibodies, reactivation of Epstein virus -Barr and a history of type 2 diabetes. These factors are not immediately visible in patients from the outset, making it difficult to predict who is ultimately most at risk for long COVID. Some studies suggest that vaccines halve the risk of adults ending up with long-lasting COVID, but other preliminary research suggests otherwise.
“Our knowledge of long COVID is definitely better today than it was a year ago,” says Ziyad Al-Aly, head of research and education at St. Louis. “But there is certainly a lot more to do, especially in the area of treatments. We don’t know yet what we don’t know.
In the lungs, where the virus typically takes root, SARS-Cov-2 can cause tissue damage and scarring that impedes oxygen delivery. But the pathogen “can affect almost any organ system,” says Al-Aly. “The heart, the brain, the kidneys.” He says scientists are still puzzled as to how a respiratory virus can cause so many symptoms outside the lungs and for so long.
A first study, published in February without peer review, combed through the health records of nearly 500,000 COVID patients in the UK to identify more than 115 long-distance symptoms that persisted after infection for at least 12 weeks. Although not all symptoms manifest in all patients, the current challenge is to link those who do to the disease, says Al-Aly. In the early stages of the pandemic, the suite of long-haul ailments was so bizarre that patient concerns were often dismissed by doctors or mistakenly attributed to psychological disorders.
Now, armed with more experience in fighting the fallout from infections, medical experts have begun to recognize common ailments among long-haulers and are working to improve treatment.
Heart and blood circulation
As a Los Angeles-based cardiologist, Alice Perlowski has always taken heart health very seriously. She was an endurance athlete and had several marathons under her belt. But since falling victim to COVID in March 2020, her blood pressure has been way over the top, she says. Her heart rate increases when she stands up abruptly – a mark of exertion for someone who was up 12 hours plus a day in the hospital before the pandemic. For the first eight months after contracting COVID, she suffered from chronic fatigue, believed to be a side effect of disrupted oxygen delivery due to blood vessel damage and blood clots.
“My job has changed 180 degrees,” says Perlowski. “My whole life has changed 180 degrees.” Her symptoms have improved to the point where she can now perform telemedicine at home.
Al-Aly and his team have conducted their own large study of how COVID ravages the heart and blood vessels, but they admit the mechanisms are still unclear. They found that the virus scars and kills heart cells, infects blood vessel walls, disrupts hormone regulation and turns the immune system against itself. These far-reaching reasons could partly explain why the disease devastates the body’s cardiovascular system and impairs the way oxygen is distributed throughout the body for normal daily function.
The nervous system and the brain
One of the most common symptoms of long COVID is what’s often called “brain fog,” a term Perlowski hates.
“Brain fog feels like you’ve been on call all night, or with a screaming baby all night, and you’re a little slower than normal,” she says. “But the type of cognitive impairment that results is such that some people have difficulty reading, writing, carrying on conversations. It’s very similar to a traumatic brain injury.
A non-peer-reviewed study published in August 2021 reported that MRI brain scans of 401 COVID patients revealed tissue damage and loss of gray matter. Brain atrophy was another common problem: on average, individuals had a smaller brain size after infection and an increased presence of cerebrospinal fluid. Patients also performed worse on baseline cognitive tests compared to people without COVID.
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Although the myriad effects of COVID on the brain are still unclear, leading hypotheses suggest the virus could infiltrate the brain through olfactory nerves or trigger immune cells to attack brain cells.
Beyond COVID’s grip on a person’s central nervous system, another insidious outcome is its impact on the autonomic nervous system. It is the network of nerves outside the brain that regulates various bodily processes running in the background of human consciousness. It governs balance and automatically adjusts heart rate and blood pressure as a person transitions from one activity to another.
Like Perlowski, longtime COVID patient Sarah (who asked PopSci not to use his real name) still finds getting up from a seated position physically intimidating. Going around his apartment is a capital feat. Going to the grocery store alone is a wild dream. Even simple cognitive tasks consume some of Sarah’s energy reserve, so she saves her daily strength to communicate with her medical care team and has no room to chat with family and friends.
Earlier this year, she tried knitting a sock. But after three rows, “I was breathing hard and so physically exhausted I had to take a nap for a few hours,” she wrote in an email. She wants the public to know “how global this handicap is”. After landing her dream job and leading an active and full life before the pandemic, Sarah now struggles daily to make sure she is simply clean and fed.
Before the pandemic, Sarah had never suffered from allergies. But in the two years since she contracted COVID, she has developed food and drug intolerances, random hives and vision problems. “I feel like I’m playing a macabre game of autoimmune/inflammatory bingo, every time a new set of symptoms pops up,” she writes.
“Long COVID symptoms really can be everywhere,” says Philip A. Chan, an infectious disease physician at Brown University. “This is the category that” I would call “other”.
These “other” symptoms can go as far as insomnia, diarrhea, hair loss, dry skin, erectile dysfunction, voice damage and body aches. The diverse and seemingly unrelated illnesses after the first episode of COVID defy categorization and highlight just how widespread the reach of the virus is throughout the body.
“We are still reminded that COVID, in general, is still a relatively new virus,” Chan says. During the first two years of the pandemic, public health policies focused on containing the pandemic. Now, after the wave of Omicron peaked and broke, Chan says it’s time to turn our attention to understanding and dealing with long COVID in the months and years to come.
There are no cures for long COVIDs yet; current treatments only address the symptoms rather than the underlying cause. “That’s one of the reasons why we have to do everything we can, of course, to prevent COVID,” Chan says. “This is yet another big reason why people should consider getting vaccinated if they haven’t.” He adds that anyone with symptoms weeks after their first COVID infection should seek help from their primary care physician as soon as possible to prevent symptoms from getting worse.
As a doctor and longtime patient herself, Perlowski has a front row seat as the disease terrorizes her and her patients. “There are people who are really in pain, who have no relief and no treatment,” she says. “It’s scary to watch.” She hopes the public is more aware of the kind of risk they face and does not let their guard down, even as daily cases and death rates improve.
Government agencies must also step up their efforts. As more states drop their COVID restrictions, long haulers like Sarah fear being left on their own. She thinks being infected with COVID again would make her not only housebound, but also bedridden. She is worried – and angry – that she will be further excluded from society as mask mandates are relaxed.
Al-Aly advises those who have fully recovered from the virus or who have escaped it so far to remain cautious and not to put additional pressure on the country’s limited health care resources. “At the end of the day, we have to face facts,” he says. “We can’t just wish for it.” Because at the end of the day, the pandemic nightmare isn’t over for the millions of long-haulers trying to survive the marks of COVID.