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Of the many who succumbed to the coronavirus pandemic worldwide, between 2020 to date, a section of Covid-19 survivors in India have reportedly developed long term lung impairment, a study found recently.
A genetical comparison between SARS-CoV-1 and SARS-CoV-2 showed interstitial abnormalities in 4.6 per cent of patients— 15 years after they had contracted SARS-CoV-1, according to Dr D J Christopher, Professor, Department of Pulmonary Medicine at Christian Medical College, Vellore.
According to Dr Christopher who is also the lead author of the study, unlike the minimal percentage of lung infection in SARS-CoV-1 survivors, the same in those who contracted SARS-CoV-2 is severe. After conducting a series of tests on 207 Covid-19 or SARS-CoV-2 survivors from the first wave of the pandemic, the study found many of these were infected with acute respiratory distress syndrome (ARDS) that is likely to result in fibrotic interstitial lung disease.
The US' National Institutes of Health defines interstitial lung disease as diffused parenchymal diseases which are a heterogeneous group of disorders characterized by scarring of the lungs. These are classified on the basis of histopathological, radiologic and clinical parameters.
Dr Christopher and his team observed the clinical symptoms of the 207 individuals 2 months after they recovered from Covid. These patients also underwent pulmonary function tests and were subjected to a 6-minute walk test, along with St George’s Respiratory questionnaire (SGRQ) and chest radiography. The mean age of the individuals part of the tests was 48.7 years of whom 141 (68.1per cent) were males.
The 207 individuals were distributed to the WHO disease severity categories as follows: mild 124 (59.9 per cent), moderate 41 (19.8 per cent) and severe & critical 42 (20.3 per cent) categories. The tests showed that around 49.3 per cent subjects suffered shortness of breath and 27.1 per cent had cough.
Another category that Dr Christopher's team focused was patients who contracted pneumonia while being Covid positive. They found that the mean lowest oxygen saturation was lower for the "Covid-19 pneumonia" group compared to the "mild Covid-19" group i.e., 94.89 vs 97.73, respectively.
Overall, the tests revealed that 44.4% had impaired diffusing capacity for carbon monoxide (Dlco). ScienceDirect decribes Dlco as an integrative measurement that describes the transfer of oxygen from the alveolus into the red blood cell. The Dlco impairment was 31.5 per cent in mild, 54.8 per cent in moderate and 73.3 per cent in severe groups.
With conclusions derived after the above tests, Dr Christopher and his team discovered that even a small degree of fibrosis in elderly patients with Covid-19, who may also have underlying lung disorders— could lead to considerable morbidity. The study that is published in PLOS Global Public Health journal further said that the team is yet to conduct follow ups on more samples from different patient groups, to understand the levels of lung damage in Covid-19 survivors.
The study also stresses on the quality of life that individuals follow, and stated that this is one of the major factors in either fueling the damage to the lungs, or reducing it through practicing effort tolerance activities.