Coronavirus patients who develop "post-Covid syndrome" brain fog and fatigue — often referred to as "long haulers" — may feel the effects for more than a year, according to a Mayo Clinic doctor studying the phenomenon.
Dr. Greg Vanichkachorn, an occupational medicine specialist, told CNBC in a phone interview Wednesday that he won't be "too shocked" if some Covid-19 long-haulers were to experience a similar, lengthy recovery trajectory as some sufferers of severe acute respiratory syndrome. SARS, a respiratory virus similar to the novel coronavirus, sparked an epidemic in 2003.
Long-hauler SARS patients back then improved, "but it took quite a bit of time, sometimes even more than a year for them to recover their function," he told "Squawk Box" on earlier Wednesday.
There are considerable knowledge gaps among researchers about what causes certain Covid-19 patients to have lingering symptoms, Vanichkachorn said. While the percentage of people who get sick with Covid-19 and go on develop post-Covid syndrome also remains unknown, he stressed that it's "not something that is rare."
At the Rochester, Minnesota-based Mayo Clinic, where he and his colleagues created a rehab program for Covid-19 survivors, Vanichkachorn said he has seen more than 100 long-hauler patients.
"I can't say there's a genetic basis for the differences in the outcomes," he said. "We, of course, have seen patients who have had more severe cases of Covid, like those patients being in the ICU or the hospital or patients of advanced age, being more likely to come down with post-Covid syndrome."
"[But] I think one of the real startling things about this is that those kind of patients, hospitalized patients or the elderly, don't make up the majority of the patients we have been seeing," he added. "In fact, many of the patients we are seeing are younger in age and are quite healthy and physically fit before their Covid infection. So unfortunately, it does seem like this is something anybody can come down with after their infection."
Short-term memory issues and concentration challenges are common symptoms experienced by post-Covid patients, Vanichkachorn said, also adding shortness of breath to the list.
The most-common symptom, however, is fatigue, he said. "It's not just like any fatigue, like the fatigue we get from a bad night of sleep but rather profound fatigue." He explained, "Patients will say that doing something as simple as taking a dog for a walk, going up a flight of steps in their home, can often result in them needing to take a nap or a rest for several hours afterwards."
People who develop post-Covid syndrome can often be stigmatized, particularly from individuals who may have recovered from Covid-19 quickly, Vanichkachorn said. However, he stressed that people who have symptoms for months should not be blamed for their condition.
Vanichkachorn advised patients to be careful as they recover from Covid-19, saying that "doing too much, too quickly" can ultimately be detrimental. "Their recovery may be longer and if they are too tired or fatigued, they really need to listen to their bodies and pace themselves," he said.