A study of the lungs of people who have died from COVID-19 has found persistent and extensive lung damage in most cases.
This finding may help doctors understand whatis responsible for a syndrome known as long COVID. People with this conditioncan suffer ongoing health problems for months.
A report on the study appeared in eBioMedicine,a medica journal published by The Lancet.
Scientists leading the research said theyfound some unusual characteristics of SARS-CoV-2, the virus that causes COVID-19.These qualities may explain why it is able to cause such harm.
One of the co-leaders of the work. Mauro Giacca,serves as a professor at King’s College London. He said the finding seem toshow that COVID-19 is not simply a disease caused by the death ofvirus-infected cells.
In some patients, he said, the seriousnessof the disease is likely the result of these cells persisting for long periodsinside the lungs.
Giacca and other researchers studied tissuesfrom the lungs, heart, liver, and kidneys of 41 patients who had COVID-19. Theyall died at Italy’s University Hospital of Trieste between February and April2020.
Giacca spoke with Reuters new agency（美[?e?d??nsi]）about the team’s finding. He said thathis research team found no clear signs of viral infection or long-terminflammation in other organs. But they did discover massive damage to thestructure of the lungs.
Healthy tissue, he noted, was almost completelysubstituted by scar tissue. Giacca told Reuters that this massive damage couldbe one of the reasons people are suffering from ling COVID.
Even if someone recovers from COVID, headded, the damage that is done could be massive.
Growing evidence suggests that a smallnumber of COVID-19 survivors can experience some ongoing symptoms. These includeextreme tiredness, unclear thinking and shortness of breath. The condition is oftencalled long COVID.
Giacca noted that almost 90 percent of the 41 patients he studied had several characteristics unique to COVID-19.
One trait was that patients had extensive blood clotting in passageways transporting blood to and from the lungs. Another
was that some lung cells were very large and had many nuclei（美[?nukli?a?]
）. This was a result of the combining ofdifferent cells into single large cells.
The researchers also found the coronaviruswas still present in many kinds of cells.
Giacca said that the existence（美[?ɡ?z?st?ns]） of infected cells can cause the major structural changes seen in lungs. These changes can last for several weeks or months and might, he added, explain long COVID.
