For example, PCT and CRP have been proven useful for helping to differentiate between pure SARS-CoV-2 or secondary bacterial infection and guiding the use of antibiotic therapy (Pink et al., 2021), and the PCT, CRP and WBC count can be combined as effective indicators for the identification of acute bacterial or nonbacterial infections in children (Li et al., 2021). This evidence concerns the gene CRP and bacterial infectious disease.