Pulmonary Involvement in COVID-19 and ‘Long Covid’: The Morbidity, Complications and Sequelae

Abstract

Introduction: the perennial pandemic: There are serious challenges posed by the SARS-CoV-2 virus and COVID-19 as the disease. With the persistence of the pandemic over one and half year, it is being feared that the COVID-19 may have become the new reality associated with human existence world over and the mankind may have to live with it for years or even decades. Further, the grievous nature of the disease is evolving further with genomic changes in the virus in form of mutations and evolution of variants, with enhanced infectivity and probably virulence. Acute and chronic phases of COVID-19: Epidemiologically, it is becoming clear that apart from the advanced age and pre-existing conditions, such as diabetes, cardiovascular, pulmonary, and renal diseases, certain constituent factors render some patients more vulnerable to more severe forms of the disease. These factors influence the COVID-19 manifestations, its course, and later the convalescence period as well as the newly defined ‘Long COVID phase. The substantial continuing morbidity after resolution of the infection indicates persisting multisystem effects of ‘Long Covid’. Lung damage associated with COVID-19: COVID-19 is primarily a respiratory disease presenting with a broad spectrum of respiratory tract involvement ranging from mild upper airway affliction to progressive life-threatening viral pneumonia and respiratory failure. It affects the respiratory system in various ways across the spectrum of disease severity, depending on age, immune status, and comorbidities. The symptoms may be mild, such as cough, shortness of breath and fevers, to severe and critical disease, including respiratory failure, shock, cytokine crisis, and multi-organ failure. Implications for the post-COVID care: Depending on the severity of respiratory inflammation and damage, as well as associated comorbidities, duration of injury and genetics, the progressive fibrosis leads to constriction and compression of lung tissues and damage to pulmonary microvasculature. Consequently, the COVID-19 patients with moderate/severe symptoms are likely to have a significant degree of long-term reduction in lung function. Depending on the severity of the disease, extensive and long-lasting damage to the lungs can occur, which may persist after resolution of the infection. Managing the long COVID’s challenges: Given global scale of the pandemic, the healthcare needs for patients with sequelae of COVID-19, especially in those with lung affliction are bound to increase in the near future. The challenge can be tackled by harnessing the existing healthcare infrastructure, development of scalable healthcare models and integration across various disciplines with a combination of pharmacological and non-pharmacological modalities. Following clinical and investigational assessment, the therapeutic strategy should depend on the disease manifestations, extent of damage in lungs and other organs, and associated complications.