As scientists try to untangle why some COVID-19 patients experience lingering symptoms for months after illness — a phenomenon also known as post-acute COVID-19 syndrome or "long COVID" — another mystery has emerged: Why are some “long-haulers” finding relief from their long-term symptoms after getting the COVID vaccine?
Ed Hornick is one of them. Hornick, a senior editor at Yahoo News, was diagnosed with COVID-19 in mid-March 2020 by a doctor in the emergency department at a London hospital. Although he recovered from the primary coronavirus symptoms in late April, by May 1 Hornick noticed the “extreme fatigue was still there and odd symptoms were appearing — mostly neurological,” he tells Yahoo Life. “I had ‘brain fog’ — a condition where a person has trouble recalling names, memories and facts. I was forgetting my friends' and family's names, repeating stories in the same sentence and not remembering, and my short-term memory was gone.”
He also dealt with “debilitating” migraine headaches — something he’d previously gotten under control with medication. “After COVID, it was as if my medicine wasn't effective anymore,” he says.
But that wasn’t all. Hornick also suffered from bad tinnitus, blurred vision, dizziness, loss of balance and coordination, heart palpitations, and muscle weakness and twitching. “I couldn't even walk a block without running out of breath and my heart racing,” he says.
Jessamyn Smyth, a professor and athlete with an immune disease, was also diagnosed with COVID-19 in March 2020 after she came down with fever and a “bizarre, sharp chest pain,” she tells Yahoo Life. “I tried hard to hold onto my work and be there for my students, about whom I was so worried. I got sicker and sicker, though, and did not get better.”
After a “life-threatening bout with COVID” over four months, in which she experienced crashing oxygen-saturation levels, the worst of her health problems started to dissipate. But Smyth noticed that her other symptoms didn’t go away: “I continued to have tachycardia [a rapid heartbeat] and chest pain,” along with trouble breathing, livedo reticularis (a vascular condition marked by a purplish skin discoloration) and joint pain.
“There was a lot of what people insist on calling ‘brain fog’ that was, for me, extreme aphasia and totally destroyed capacity to concentrate or accomplish work,” Smyth says, “and there was a lot of what people insist on calling ‘fatigue’ that was, in fact, absolutely knock-down-pass-out-for-15-hours pathological exhaustion.” She adds: “I learned that all this is common to many long-COVID people.”
Smyth and Hornick are far from alone. Experts estimate that 10 to 30 percent of COVID-19 patients experience long-term symptoms. A February research letter published in JAMA Network Open followed up with more than 170 patients up to nine months after they'd been diagnosed with COVID and found that about 30 percent reported persistent symptoms, even though many people in the study reported only mild illness. Fatigue was the most common symptom, followed by the loss of smell or taste and brain fog.
Dr. Bradley Sanville, who helped start the post-COVID-19 clinic at UC Davis Health in Sacramento, Calif., tells Yahoo Life that the “classic post-COVID symptoms I see most frequently” include brain fog, fatigue, shortness of breath and chest pain.
However, for some people suffering from long COVID, the vaccine comes with a surprising side effect: They get better.
For Smyth, everything changed a couple of weeks after she got the COVID-19 vaccine in February. “The fatigue and aphasia got noticeably better, and I realized I hadn’t had livedo reticularis or COVID toes or chest pain since the shot,” she says. “It was way beyond an emotional relief or stress-reduction reaction.” She adds: “I began to feel like myself for the first time in a year.”
After Hornick got his first COVID vaccine in March, he experienced “flulike symptoms” for several days. But by day five, he noticed that he felt surprisingly “good.” One of the long-term symptoms he’d struggled with the most — brain fog — had “dissipated altogether,” he says. And although he still had headaches, they weren’t as bad as they had been. “I felt clearheaded and didn't have the usual trouble with memory, recall and comprehension. So far, it has stuck.”
While Hornick is not free from all of his lingering post-COVID symptoms — he still experiences chronic fatigue, tinnitus, tremors and spasms — he feels relieved about this sudden change.
“For the first time in a long time, I have hope that my overall health may improve,” he says. “I'm hoping that over time, the remaining symptoms start to dissipate — or at least become more manageable — so I can live a normal, productive life.”
However, “nobody is entirely sure why people are getting long COVID to begin with,” says Sanville.
It’s also not yet clear why some post-COVID symptoms resolve more quickly than others. “For example, fevers, chills and taste/smell-associated symptoms typically resolve within two to four weeks, while fatigue, dyspnea [shortness of breath], chest tightness, cognitive deficits and psychological effects may last for months,” Dr. M. Rizwan Sohail, a professor of medicine specializing in infectious diseases at Baylor College of Medicine, tells Yahoo Life.
Further adding to the mystery is how the vaccine might be helping long-haulers like Hornick and Smyth. But immunologists and virologists have some theories. “One is that a small amount of virus reservoir remains in the body after initial infection,” explains Sohail. “This residual virus or its genetic material causes ongoing low-grade inflammation and symptoms related to long COVID. Another possibility is that vaccine-induced immune response leads to a ‘hard reset’ of the immune system. And because immune dysfunction — according to this hypothesis — is the cause of longer-term symptoms, a reset leads to symptoms resolution.”
Sanville says he’s had several long-COVID patients whose symptoms improved after they received the vaccine. “I’ve had a few people who have gotten back entirely to normal lives,” he says. But Sanville points out that this doesn’t happen to every patient who receives the vaccine. “Why that develops in some people and not others is not clear,” he says. “Not every patient has that effect.”
Sohail says these “unexpected benefits of the vaccine are both surprising and exciting.” However, at this point, he says, “we do not know, and neither can accurately predict, which patients with long COVID will benefit from this particular aspect of vaccination. Therefore, we need more data before we can counsel patients about this.”
Sanville agrees: “Whether it was the vaccine that did it or the timing was right for getting back on their own, it’s nice to, hopefully down the road, get some information about what exactly the mechanism is and whether that’s a verifiable treatment.”
So should patients who have recovered from COVID still get the vaccine? Yes, according to Sanville and Sohail. Although they develop natural antibodies after having the illness, “some of the patients with COVID do not develop sufficient levels of protective antibodies to prevent reinfection,” notes Sohail. “Therefore, we recommend that patients with a history of COVID strongly consider getting the vaccine.”
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