Three-quarters of Covid-19 patients still have at least one symptom six months after first falling ill, researchers who followed hospital patients in China reported Friday. The new findings suggest symptoms linger longer and in a higher proportion of patients than previously thought.
The largest and longest analysis to date of post-Covid recovery also warns that some patients’ antibody levels fell sharply, raising concern that while waiting for a return to full health, they could be reinfected with the coronavirus.
Almost two-thirds of the patients said they were still suffering from fatigue and muscle weakness, the researchers wrote in The Lancet. A little over a quarter had difficulty sleeping, and a little under a quarter experienced anxiety and depression. Overall, more women than men reported lingering symptoms, and people whose disease was more severe had poorer lung health. Their median age was 57.
Earlier studies looking at Covid-19 “long haulers,” the term for people whose well-being does not return after their infections clear, had been limited by time and numbers of cases. A July estimate from the Centers for Disease Control and Prevention said 1 in 3 people still have symptoms that linger for two or three weeks. A survey conducted in the U.K. concluded in November that 1 in 5 people suffered from symptoms lasting five weeks or longer; 1 in 10 said their problems lasted 12 weeks or longer.
The larger number of patients studied in China, where the pandemic first unfolded, and the higher proportion of people experiencing difficulties for a longer time paint a picture of problems that aren’t going away.
“I am most worried about the unknown future for these patients’ recovery. At six months after symptoms onset, a considerable proportion of Covid-19 patients had physical and psychological problems,” study co-author Lixue Huang of the China-Japan Friendship Hospital and Capital Medical University told STAT. “We still do not know how long it takes for these patients to recover fully from Covid-19 or whether complete recovery is possible in every case.”
Dr. David Putrino, who works with patients in Mount Sinai’s Center for Post-COVID Care, warned against overreacting to the high percentage of people reporting at least one lasting symptom, calling it a mistake to characterize all of them as long haulers. He was not involved in the study.
“Within that 76% there are people who are long haulers, people who have long-term cardiac damage because of Covid infection, people who have long-term lung damage and kidney damage, and so on.” he said. “And then my suspicion would be that a large number of individuals are having pretty mild but reportable symptoms.”
Shortness of breath or loss of smell six months later are troubling, but they are not the debilitating symptoms he sees in long haulers, Putrino said.
“This is not to discount these lived experiences, not to say it’s not terrible. It is terrible that at six months post-virus people are still feeling symptoms,” he said. “That really tells us how serious this thing is, but we also need to make sure we report that many of these are very mild symptoms.”
The study, co-author Bin Cao of the National Center for Respiratory Medicine said in a statement, “highlights a need for post-discharge care, particularly for those who experience severe infections. Our work also underscores the importance of conducting longer follow-up studies in larger populations in order to understand the full spectrum of effects that COVID-19 can have on people.”
For the study, more than 1,700 people treated for Covid-19 at Jin Yin-tan Hospital in Wuhan between January and May 2020 answered questions from June through September about their symptoms, gave blood samples, and took a six-minute walking test. Almost 400 also took lung function tests and had CT scans to evaluate their health. Antibodies were tested in the 94 patients who had previous readings taken when their infections were at their peak.
Levels of neutralizing antibodies — the immune cells that learn from infection to attack the virus when they see it again — fell by half in the patients with before-and-after readings, signaling a need for larger studies to see if reinfection is a potentially serious problem these patients may face.
In another complication, 13% of patients who had normal kidney health when they were in the hospital later had reduced kidney function, the study found. That’s a red flag for people who already have potential risk factors for kidney damage, such as high blood pressure and diabetes.
As expected, people who needed help breathing while they were in the hospital performed worse on the walking and lung function tests, and CT imaging revealed damaged lungs. Only 4% of the patients in the study were treated in ICUs, so other studies will be needed to draw more conclusions, notes an editorial accompanying the Lancet study.
Fred Pelzman, who practices internal medicine in New York and was not involved in the study, said the experiences of patients in China square with what has been happening in the United States.
“It certainly is compelling evidence that there are a lot of people with a lot of persistent symptoms,” he said. “We’re seeing in our post-Covid recovery clinics that people are coming in with cardiomyopathy and neuropathies and cognitive changes and balance changes. This is just a virus our body hasn’t seen before that has an enormous inflammatory response, so it’s not surprising that every organ system is upset.”
Predicting the future for long haulers is difficult, Pelzman said, in part because some symptoms may be a consequence of hospitalization, including difficult stays in intensive care units that mean patients have to relearn how to walk when they are discharged. He is not surprised by the drop in antibody levels, saying the body’s immune system isn’t designed to stay on high alert at all times.
“We don’t know yet if your immunity lasts six months or nine months or a year or 10 years,” he said. “The interesting thing will be what happens when someone is exposed again. Do they have a rise of those antibodies again? How long does that efficacy persist?”
Pelzman himself was infected with Covid-19 in March.
“It definitely has lingered,” he said. “I can get a little winded on Zoom calls. I walk home from work and I get a little out of breath, and a couple foods taste funny still. But you know, I’m alive and so I’m OK.”