Importantly, the strong staining of complement components mannose‐binding lectin (MBL), C4, C3, C5b‐9, in alveolar epithelial cells, inflammatory cells, pneumocytes, and exudates in alveolar spaces in the patients who died from COVID‐19 accentuated the role of complement system during pathogenesis of COVID‐19. Here, C4A is linked to COVID-19.