The longterm effects of Covid-19 on lung tissue are still unknown. Photo / AP
In two early studies, researchers said some patients showed signs of healing just weeks after leaving the hospital.
When Annie Coissieux tried to stand up for the first time after weeks in the hospital battling Covid-19, she couldn't get on her feet.
"My first day after ICU, I couldn't leavethe chair without the help of two nurses," she recalled from her home in the Drôme region in southeast France. She felt breathless and exhausted after walking for just a few minutes. "Going to the bathroom was a real mission that required time and effort."
Coissieux, 78, was sent to a nearby pulmonary rehabilitation clinic, Dieulefit Santé, where a physical therapist taught her exercises to help restore her lungs and the muscles involved in breathing.
When she went home three weeks later, Coissieux could walk close to 300 metres with a walker. As she exercised at home, she grew stronger. "Now I can walk 500 meters with no walker," the retired schoolteacher said. "I can walk up the stairs at my cousin's house." And while she still feels fatigued in the afternoons, she cycles on her indoor bike and swims.
Lingering shortness of breath and diminished stamina have dogged many Covid patients whose lungs were viciously attacked by the coronavirus. Early in the pandemic, doctors worried that Covid might cause irreversible damage leading to lung fibrosis — progressive scarring in which tissue continues to die even after the infection is gone.
According to the World Health Organisation, about 80 per cent of patients have mild to moderate symptoms, 15 per cent develop a severe form of the disease and about 5 per cent like Coissieux escalate to critical.
While global or nationwide statistics on post-Covid lung recovery are not yet available, hospitals and clinics are assessing their cases.
At the peak of the outbreak in New York, about 20 per cent of hospitalised patients were in intensive care units, where many needed ventilators, according to Dr. Gabriel C. Lockhart, a pulmonologist at National Jewish Health, a respiratory hospital in Denver, who also volunteered at the Mount Sinai Hospital in New York. "Of the ones who get intubated, at least two-thirds will survive but will require some physical therapy," he said.
It's not known yet how many people will rebound to their pre-Covid status, because so many are still recovering, said Dr. Jafar J. Abunasser, a pulmonologist at Cleveland Clinic. He added that one study of severe acute respiratory syndrome, another coronavirus, published in the journal Chest found that about 59 per cent of survivors had no lung impairment after one year, while one-third still had some lung abnormalities, which he described as "mild."
During this year's pandemic, few patients suffered such severe lung damage that they required lung transplants, still a rarity worldwide. But that number may climb as some patients' lungs will not improve sufficiently, said Dr. Sadia Shah, a pulmonologist at the Mayo Clinic in Jacksonville, Florida.
At a recent European Respiratory Society meeting, doctors presented early results of a few small studies that offered a glimmer of hope, indicating that in at least some cases, patients' lungs show signs of recovery, especially with intensive aftercare and exercise.
Yara Al Chikhanie, a doctoral student in lung physiopathology at the Dieulefit Santé, cited the clinic's rehabilitation study of 19 patients at the session.
For patients who were bedridden or intubated in intensive care units for weeks, the ability to breathe on their own was impaired. Their muscles, including the diaphragm — the main breathing muscle that pushes the abdominal organs down so that the lungs can expand — had weakened.
"They spent months in bed and lost their muscle and respiratory capacity," Al Chikhanie explained.
"It seems that most of these more severe patients recover from severe lung injury," said Dr. Frederic Hérengt, who oversaw the study at Dieulefit Santé.
Longer-range studies still have to be conducted to assess the potential for permanent effects.
Doctors at the University Clinic of Internal Medicine in Innsbruck, Austria, observed similar improvements in their 86 patients, who were also in the hard-hit category and endured long hospital and ICU stays.
Even after rehabilitation, many were still coughing and short of breath as they went home, equipped with exercise instructions and breathing devices — small, inexpensive plastic tubes that require one to breathe in and out with force.
But as they came back for checkups weeks later, their CT scans showed improvement, doctors said. Fluids were clearing from their lungs, and the white-glass lesions often seen in Covid pneumonia were lessening, sometimes disappearing and sometimes noticeable only as thin white bands.
"There are some signs of reversible damage," said Dr. Thomas Sonnweber, who conducted the study with his colleagues Dr. Judith Löffler-Ragg and Dr. Ivan Tancevski. At the time the patients were discharged from the hospital, 88 per cent had lung damage, but 12 weeks later, only 56 per cent did.
Their symptoms also improved. They coughed less, breathed and walked more easily, in some cases with markedly improved endurance.
"We have seen patients who went on wheelchairs to rehabilitation but they start walking again," Löffler-Ragg said. She cited one particular case of an elderly man who needed oxygen before rehabilitation, but now walks up the stairs to his fourth-floor apartment with only mild shortness of breath. "Despite his 78 years, despite Covid pneumonia, he can manage this," she said.
Neither study has been peer-reviewed or published in a scientific journal. But the patients' improvement was encouraging to others who have been treating patients.
Our lungs have good inner healing mechanisms, said Dr. Panagis Galiatsatos, an assistant professor who specialises in pulmonary and critical care at Johns Hopkins Bayview Medical Center in Baltimore.
The infection leaves behind a mess of dead cells, damaged tissues and fluids, caused by the coronavirus and the overzealous response of the immune system that often occurs in Covid patients. But once the infection is gone, the lungs begin to rebuild themselves, using specialized cells devoted to healing.
"They create new cells to replace the diseased ones," Galiatsatos said. "There are also other cells that try to not only create new cells but promote the architecture of the lungs — not just recreating it, but recreating it to look exactly as it did before."
When that's not possible, scars will form and some may become permanent, but that serves a purpose too. The lungs know that the scarred spot can't perform oxygen exchange, so they won't send blood there. "It's called a shunt," Galiatsatos said, adding that the lungs will adapt. "They're going to send the blood to the more healthy parts." Breathing and physical exercises can aid this recovery.
Doctors don't yet know how long it will take patients to regain their pre-Covid strength and endurance. In the case of acute respiratory distress syndrome or ARDS, which has been caused by other viruses and has similarities to Covid-19, full recovery can take over a year, but there are no such statistics for Covid yet.
However, the earlier patients start their rehabilitation, the faster they begin to bounce back, which may be another reason for doctors to take them off ventilators sooner, Al Chikhanie said. That may be possible, especially as scientists understand how to manage the acute infection phase better.
Some people who spent a long time on life support can recover, although they will need a great deal of help and perseverance. "Stay active, move and walk around the house, go up and down stairs," Al Chikhanie said.
But research is still very nascent about finding the best therapies to help COVID survivors restore their strength and lung capacity. "We really need a couple of years of data, it's far too early for us to have the data about this pandemic," Abunasser of the Cleveland Clinic said.