By Julia Ries
Scientists have learned a ton about COVID-19 in record time, but there are still a lot of uncertainties about the novel coronavirus and the disease it causes.
One of those mysteries is “long-haul COVID”: People get COVID-19, recover, then experience lingering symptoms for months.
Because COVID-19 has only been around for a year, we have yet to fully understand the long-term health effects of the disease.
We’re just now starting to see that COVID-19 doesn’t always disappear when the infection clears up. In some cases, the infection triggers serious long-term physical and neurological health effects.
A new studyTrusted Source published this month in The Lancet found that 76 percent of people who had been hospitalized for COVID-19 still had at least one symptom 6 months after recovering.
In general, the more sick a person was with COVID-19, the greater their risk of experiencing persistent symptoms months later.
But even mild cases have been linked to lasting painful symptoms.
“The biggest takeaway is that the susceptibility to persistent symptoms in COVID-19 is unpredictable, not necessarily dictated by how severe symptoms were during acute COVID-19, or other typical risk factors such as age or other comorbid conditions,” Dr. Serena Spudich, a Yale Medicine neurologist, told Healthline.
Long-term symptoms are common
The studyTrusted Source looked at 1,733 people diagnosed with COVID-19 in Wuhan, China, and tracked their recovery from June to September.
The researchers found that 76 percent of 1,655 study participants at follow-up were still experiencing symptoms 6 months after recovering.
Those symptoms were most commonly fatigue and muscle weakness, which 63 percent of them reported. Many others experienced anxiety, depression, pain, and sleep difficulties.
Those who had severe COVID-19 were more likely to experience lingering respiratory issues, which the researchers suspect may be due to lung damage.
Some participants went on to experience kidney issues. Nearly 13 percent of participants who developed kidney problems at follow-up had normal kidney function while in the hospital for COVID-19.
Dr. Teresa Murray Amato, the chair of emergency medicine at Long Island Jewish Forest Hills in New York City, says the study confirms her hospital’s anecdotal experiences with the lingering health effects of COVID-19.
“We have seen a number of patients that had COVID infections in the spring of 2020 still with symptoms despite their recovery,” Amato said.
She noted that fatigue and muscle pain are the two most common long-haul symptoms her team has seen.
What we’ve learned about long-haul symptoms
In response to the increasing number of people reporting long-haul COVID-19 symptoms, healthcare systems have opened clinics dedicated to diagnosing and treating this group.
Yale Medicine opened a clinic specifically tailored to post-COVID-19 complications.
“All too commonly, we are seeing patients with shortness of breath, fatigue, chronic pain, memory issues, and depression,” said Dr. Jean Paul Higuero-Sevilla, a physician at Yale Medicine who works in the Post-COVID-19 Recovery Program.
Lingering symptoms are present in people of all ages and not only in those who had severe COVID-19, but after mild cases, too.
“Some of our patients were diagnosed with COVID during the first wave of the pandemic and are still dealing with long-term health consequences,” Higuero-Sevilla said.
Many of these people experience neurological issues, so Yale opened a second clinic, called neuroCOVID, for people with symptoms involving the brain and nerves.
“These include a fairly wide variety of symptoms, including problems with memory and concentration, unremitting headaches, abnormal sensations on the skin, prolonged loss of smell and taste, and difficult symptoms of new or worsened anxiety and depression,” said Spudich, who runs the neuroCOVID clinic.
Long-haul COVID-19 can have a devastating impact on people’s ability to carry on with their daily lives.
“We are seeing many patients with cognitive difficulties that are impacting their ability to feel confident at work or back in their studies at school, related to challenges with attention to duties, ability to multitask, or difficulty with learning new information,” Spudich said.
What’s causing long-haul COVID-19?
The researchers suspect a mix of factors could be causing these lingering symptoms, including lasting issues from the initial infection, an overactive immune response, corticosteroid therapy, a stay in the intensive care unit, social isolation, and stigma associated with the disease.
“We have a lot to learn about what is behind these symptoms, but we know that some patients with COVID-19 have inflammation in the body with the acute infection,” Spudich said. He added that inflammation might persist after the infection clears.
Some scientists suspect the immune system may continue to fight the infection even after it clears, further damaging organs.
Amato said it’s difficult to pinpoint the root cause of the psychological issues.
“It is also difficult to surmise if the increase in mental health issues are a direct effect of the virus or caused by the other lasting physical effects, prolonged isolation of the pandemic, or other factors,” Amato said.
It’s largely a mystery why some people develop long-haul symptoms and others don’t, according to Spudich.
“Some of our patients are in their 30s, while others are in their 60s. Some were very sick in the intensive care unit during their acute COVID-19 illness, while others were never hospitalized and endured their illness at home,” Spudich said.
The risk factors aren’t clear, but Spudich suspects genetics and abnormal immune and inflammatory responses could be the determinant risk factors.
This coronavirus is still new, so we have yet to see and understand its lasting effects.
“More research is needed to better understand the causes, length of symptoms, and any intervention that may help,” Amato said.
The bottom line
New research has found that 76 percent of people who had been hospitalized for COVID-19 experienced at least one lingering symptom 6 months after recovering.
Long-term symptoms affect people of all ages and have occurred in people with mild, moderate, and severe COVID-19.
It’s unclear what’s behind long-haul COVID-19, but doctors suspect the risk factors include genetics, inflammation, and abnormal immune responses.