Alternatively, a different infection might have caused the early sepsis presentation, with clinical improvement up to day 4 related to appropriate treatment with antibiotics, after which COVID-19 manifested on day 5, causing clinical worsening. However, no infection other than SARS-CoV-2 was identified by culture, pathology, or respiratory viral panel, procalcitonin concentration was normal in the first 48 h (appendix p 1), serum and BAL galactomannan were negative, and the pathological finding of acute lung injury in the lesion was already present on day 2, which argue against this explanation.