POC MxA levels (median [IQR]) were higher in children (n = 18) with a microbiologically confirmed viral infection without bacterial infection (785 [558–1001] μg/L) compared to children (n = 17) with a bacterial infection without viral infection (25 [25–25] μg/L, P < .001) (Supplementary Figure 1). The gene discussed is MX1; the disease is viral infectious disease.