As the coronavirus disease 2019 (COVID-19) pandemic continues to wreak havoc across the globe, some people who recover from the infection have reported persistent symptoms surrounding the lungs, such as difficulty breathing. A small fraction of people have also reported having other lasting symptoms; these individuals have been dubbed "long haulers" or "long-COVID” patients.
COVID-19, caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is a respiratory illness that primarily targets the lungs. However, many other organs can be affected, especially in severe cases.
A team of researchers at the University of Trieste in Italy aimed to determine the extent and the causes of lung damage from COVID-19 to better understand the pathological correlates of the disease.
To arrive at the study findings, which appeared in the journal EBioMedicine, the researchers performed a systematic analysis of 41 consecutive post-mortem samples from people who succumbed to COVID-19. The team conducted a histological analysis for cellular and viral antigens and to detect the presence of viral genomes.
The researchers reported that of the 41 cases analyzed, six required intensive care, while 35 were hospitalized until they died. The average age of the patients was 77 for males and 84 for females. The common comorbidities seen in the patients were hypertension, chronic cardiac disease, dementia, diabetes and cancer. All of the patients died of acute respiratory distress syndrome (ARDS), a condition caused by severe SARS-CoV-2 infection.
When the team conducted a pathological examination, all cases manifested lung damage. When assessed physically, the lungs appeared congested. In 4 out of the 41 cases, the team observed thrombosis in large pulmonary vessels. Further, tissue analysis showed vast damage to the normal lung anatomy, consistent with a condition of diffuse alveolar damage with edema, bleeding, and intra-alveolar fibrin deposition with hyaline membranes.
"It could very well be envisaged that one of the reasons why there are cases of long COVID is because there is a vast destruction of the lung (tissue)," Mauro Giacca, a professor at King's College London who co-led the work.
"Even if someone recovers from COVID, the damage that is done could be massive," he added.
He added that almost 90 percent of the 41 patients experienced many characteristics unique to COVID-19 compared with other forms of pneumonia. Meanwhile, the researchers said that the heart, liver and kidney presented common features of age-related tissue degeneration in all the patients, but the tissue integrity was essentially preserved.
In a nutshell, the team detected additional hallmarks that can characterize the COVID-19 disease process. First, there is the presence of massive lung thrombosis, persistent viral infection, endothelial dysfunction, as well as the presence of dysmorphic cells in the lungs.
"In light of the persistence of virus-infected cells in the lungs of infected individuals and the peculiar molecular features of the SARS-CoV-2 Spike protein we propose that several of the clinical characteristics that set COVID-19 apart from other interstitial pneumonia are not attributable to pneumocyte death as a consequence viral replication, but to the persistence of virus-infected, Spike-expressing cells in the lungs of the infected individuals," the researchers concluded in the study.
The coronavirus disease often affects the elderly and those with comorbidities and underlying medical conditions. Across the globe, there more than 47.67 million cases, and of these, about 1.21 million have died. The United States remains the nation with the highest number of infections, topping 9.40 million, followed by India, with at least 8.31 million cases.
It has been 11 months since the emergence of the virus in Wuhan City in China. As yet, there is still no cure or vaccine against the virus. The best way to reduce the risk of being infected remains the usual preventative measures: washing the hands regularly, practicing social distancing, and wearing masks.
- Bussani, R., Schneider, E., Zentilin, L., Collesi, C., Ali, H., Braga, L. et al. (2020). The Lancet. https://www.thelancet.com/journals/ebiom/article/PIIS2352-3964(20)30480-1/fulltext#%20