Covid 19 or SARS -COV-2 infection originated in Wuhan city of China towards the last week of 2019 which was declared as pandemic by WHO on February 11 2021. Corona virus belongs to Nido virus which is a large family of viruses causing a wide variety of infections ranging from common cold to major organ dysfunction such as acute respiratory syndrome and multi organ failure. As there was no immunity against the novel Covid 19 virus, this virus has affected the whole world through its mutant variants resulting in rapid spread. Clinical course is characterized by an initial viremic phase where most people remain asymptomatic, around 80% will have mild to moderate symptoms, 15% progress to severe covid and 5% become critically ill. Second stage which lasts for 4-10 days after symptom onset where viral replication persist and moderate disease develops resulting in viral pneumonitis, some times other organ also can be affected. Stage 3 occurs 6-15 days from the initial symptoms which is characterized by severe respiratory illness, multiorgan dysfunction, immune cell exhaustion and hyperinflammation resulting in cytokine storm in some patients. Hence it is desirable to look into the immuno pathology of Covid 19 infection and to assess the effectiveness of anti viral therapy, immunomodulation therapy and immune suppressant therapy apart from the respiratory and other supportive measures to these patients.
