While most people who contract COVID-19 will later test negative for the virus and recover weeks after infection, an undetermined percentage of people who also test negative continue to report . Testimonies from people in this group, known as who say they found relief after receiving the vaccine, have offered a new clue into the ongoing mystery of so-called "long COVID."
"This is real, this is not imaginary. These are people whose symptoms are real," Dr. Anthony Fauci said of long COVID at a Senate hearing on Wednesday. The director of the U.S. National Institute of Allergy and Infectious Diseases said anywhere from 25% to 40% of individuals who test positive for COVID-19 "have prolongation of symptoms that measure not only in weeks, but in months," some of which, he added, "become completely incapacitating."
Long COVID commonly manifests as persistent severe fatigue, difficulty with thinking and concentration, known as "brain fog," a heart rate that speeds up with no activity, severe exhaustion despite limited activity, loss of smell and taste, pain like pins and needles in the hands and feet, and an array of other symptoms, according to Dr. Jason Maley, program director of the Critical Illness and COVID-19 Survivorship Program at Beth Israel Deaconess Medical Center in Boston.
The Centers for Disease Control and Prevention also lists shortness of breath, coughing, joint pain, and chest pain as common long-term symptoms. Maley said most of the symptoms his patients report differ from what they initially experienced from COVID-19.
Dr. Bradley Sanville, a pulmonologist at UC Davis who treats long COVID patients at the facility's Post-COVID Clinic, said the most common symptom he encounters is an overwhelming sense of fatigue, but noted that "symptoms are extremely varied."
"We don't necessarily have a definition yet of long COVID," he said, "... a lot more theories than clear science."
One thing that both doctors have witnessed, however, is an improvement in some patients after receiving. Maley said about a third of his long COVID patients improved after the vaccine. Sanville said almost 50% of his patients say they felt improvement after the vaccine — several "within a week after vaccine."
"More common thing is that people seem to feel better with it," Sanville said.
Vaccines prepare the body to fight off future infections by providing it with a supply of "memory" white blood cells that remember how to fight that virus if encountered again. Why the COVID-19 vaccine appears to ease or end some people's long-term symptoms is not known, but Maley said it could be that persistent virus in the patient is being cleared, or maybe an immune response is triggered.
"It's hard to say more than that because it's just an area that's not known," he said.
CBS Denver medical editor Dr. Dave Hnida has been looking into the cases. "We think what's going on is that in a lot of these cases there are people who carry little viral particle remnants in their blood. There are also theories that have to do with a hyper-immune response," Hnida told the station. "Vaccination does something to the body and winds up decreasing that hyperactive immune system or immune response."
The doctors stressed that formal studies are still needed. "Multi-year studies are underway," according to the CDC. "CDC continues to work to identify how common these symptoms are, who is most likely to get them, and whether these symptoms eventually resolve."
Fauci touted a $1.15 billion appropriation given to the National Institutes of Health specifically to study long COVID on Wednesday. "You will be hearing more announcements, not only to understand the scope of the cohort, but the underlying cause and what the mechanisms are," he said.
Asked if the vaccine could help long-haulers, Fauci emphasized that anecdotes of recovery after vaccination are still only that: anecdotes. "The reason I say 'anecdotal' is because many people spontaneously get better anyway, and if you get vaccinated and you get better you're not sure if it's the vaccine or spontaneous recovery," he said. "So you'll have to do a randomized trial in order to determine that."
While improvement after the vaccine is not proven, Maley and Sanville both recommended that long COVID patients should get whatever vaccine is available to them, in consultation with their own physicians. "Some people it's almost a year out at this point and they're still symptomatic," Sanville said, adding, "I've been telling people there's no reason they shouldn't (get the vaccine)."
One study of long COVID released this month by doctors in the United Kingdom found that vaccination "was not associated with a worsening of Long Covid symptoms, quality of life, or mental wellbeing." The study — which has yet to be peer reviewed — concluded that "individuals with prolonged COVID-19 symptoms should receive vaccinations as suggested by national guidance."
The CDC has not released vaccination guidance specifically for long COVID sufferers. According to its website, "people with COVID-19 who have symptoms should wait to be vaccinated until they have recovered from their illness and have met the criteria for discontinuing isolation; those without symptoms should also wait until they meet the criteria before getting vaccinated."
Patients who continue to suffer long after their COVID diagnosis are first evaluated to rule out damage caused by the initial infection. "There are two types of long-term concern," Fauci explained. "There's an individual who might get mild to moderate symptoms, may or may not be in the hospital, and winds up getting symptomatology, like fatigue... but there are also those who get considerable organ system damage."
"I made rounds myself on a patient about four days ago at the NIH clinical center, where the extent of disease that person has... even if they do recover, almost certainly they are going to have prolongation of dysfunction in multiple organ systems," he said. "So it's not only the long COVID, it's also people who have damage to their heart, to their lungs, to their kidney. Those are the things that we're also concerned about."
If damage is ruled out, long COVID patients are currently treated based on the symptoms they present.
"(We) focus on what their specific symptoms are and how their life is affected by those symptoms," Maley said. The gamut of symptoms mean that long COVID patients end up seeing a variety of doctors. Sleep issues, which Maley said are "almost universal," could stem from a number of causes, for example, but may be treated by a sleep specialist.
Sanville pointed out that the breadth of symptoms is likely a reason why formal studies into long COVID are still rare: "It's not clear what the problem is, so it's hard to know what therapeutic avenue to go down."
"Once we understand that," Fauci said, "then we can start talking about designing therapies."