While a longer recovery course might be expected for someone such as Herbert who faced a more severe illness, there’s also concern for more permanent lung damage, according to Dr. Ronald DePinho* – co-founder of Tvardi Therapeutics. DePinho is particularly worried that the immune response to Covid-19 may cause irreversible scarring known as pulmonary fibrosis.
Pulmonary fibrosis can be a “relentlessly progressive” disease of the lungs in which patients can become dependent on oxygen or even ultimately require lung transplants, he said. Again, this is after a patient is thought to have “recovered.”
Though it’s too early to know whether patients with the novel coronavirus will develop this sort of lung scarring, studies in other related coronaviruses, such as SARS and MERS, suggests certain Covid-19 patients may have lasting fibrosis. One study following 36 MERS patients found a third still had lung fibrosis on chest x-rays after a median follow-up of 43 days.
And up to two-thirds of patients with SARS who were sick enough to require hospitalization also developed pulmonary fibrosis, according to DePinho. If the same pattern holds true for Covid-19, that could mean many thousands of people will have long-term lung scarring, he said.
The data from China thus far is still thin, but the early results follow the same pattern DePinho is describing. In a study of 63 Covid-19 patients from Wuhan, China, about 18% had “fibrous stripes” on CT scans. And in another study, it took more than 6 weeks for one patient’s chest CT to return to normal, even though his symptoms had already improved.
This might explain why some patients have significant drops in their lung function even after recovering from the novel coronavirus. Losses in lung function could be as high as 20 to 30 percent, the medical director of infectious diseases at Princess Margaret Hospital in Hong Kong told a media briefing in March.
*It’s important to note the comments made during this interview are Dr. DePinho’s personal opinion and do not relate to his role at MD Anderson.