CRP and bacterial infectious disease: The extreme inflammation is usually evidenced by elevated serum of CRP, IL-6, and PCT which indicate the increasing of COVID-19 severity.27 High levels of CRP and procalcitonin in COVID-19 patients also associated with the progression of ARDS, myocardial injury, and death.27,28 The presence of secondary bacterial infection would be an additional explanation of this increase in inflammatory biomarkers.