Post-COVID-19 Pulmonary Fibrosis: An Update

Coronavirus disease 2019 (COVID-19) is caused by a novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The most common cause of hospitalisation for COVID-19 is interstitial pneumonia that may be complicated by Acute Respiratory Distress Syndrome (ARDS). With an increasing magnitude of COVID-19 survivors, post-COVID interstitial lung disease and pulmonary vascular disease are likely to be the most important long term respiratory complications. Data from previous coronavirus infections such as Severe Acute Respiratory Syndrome (SARS) and Middle East Respiratory Syndrome (MERS), as well as emerging data from the COVID-19 pandemic, suggest that there could be substantial pulmonary fibrotic consequences following SARS-CoV-2 infection. Thus, the long-term consequences of COVID-19 appear crucial. Here, we have discussed the pathogenesis, natural history, and radiological aspects of such patients and the possible predictors which might lead to the development of lung fibrosis. Older age, severity of illness, prolonged ICU stay, history of smoking and alcoholism are few of the risk factors for the development of post-COVID-19 pulmonary fibrosis. Therapeutic options like antifibrotic drugs such as pirfenidone, nintedanib, pulmonary rehabilitation, SARS-COV-2 vaccine etc. have been described. The role of steroids and antifibrotics in the prevention of post-COVID fibrosis is still controversial. Careful longitudinal follow-up of multiple cohorts of post-COVID-19 survivors with serial lung function testing and imaging is required to complete the knowledge about natural history of the disease and the response to various therapies.