By Clare Wilson

Artyom GeodakyanTASS via Getty Images

People infected with the coronavirus may be left with permanent lung damage. Doctors are reporting growing numbers of people who still have breathlessness and coughing months after falling ill with covid-19, and who show evidence of irreversible lung scarring on chest scans.

The numbers of people affected are not yet known, but estimates are as high as one in five of those who needed intensive care treatment for covid-19. Permanent damage is sometimes seen after other kinds of chest infections that can cause similar lung inflammation to the coronavirus, such as flu and pneumonia.

“We have always seen this before – what’s different is the scale of this,” says James Chalmers, a chest physician and advisor to the British Lung Foundation. Previously his clinic in Scotland would have seen post-infection scarring of the lungs just once or twice a year, he says. “Now we are seeing dozens of patients coming through.”

In a study in Italy, which was one of the first European countries to be hit by the coronavirus, doctors are scanning the lungs of people three months after they fell ill. Although the full results are not yet in, Paulo Spagnolo at the University Hospital of Padua estimates 15 to 20 per cent of those treated in intensive care at his hospital have scarring. “We have to be prepared in the future to manage these patients.”

In most people the coronavirus causes only mild symptoms, but in some it leads to serious lung inflammation and an excess of immune signalling chemicals, leading to a complication called a cytokine storm. “If left unchecked the inflammation starts to cause damage and scarring,” says Chris Meadows, an intensive care doctor at Guy’s and St Thomas’ NHS Foundation Trust in London.

If someone is left with scarring, also known as fibrosis, there is no way to reverse it, says Chalmers. All people can do is try improve their aerobic fitness to compensate for their lower lung function and learn to cope with breathlessness.

As well as scarring, there may be other mechanisms that cause long-term problems. Severe covid-19 makes blood more prone to clotting, so people develop tiny clots in the blood vessels of their lungs. To compensate, new blood vessels grow, but these can be disorganised, leading to high blood pressure in their lungs. “You don’t get as much oxygen,” says Chalmers.

Lung damage is not confined to people who needed ventilation, he says. “More severe covid means more likelihood of permanent damage, but I have got a couple of patients who were not on ventilators and have long-term complications.”

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