Host-response biomarker MxA for etiological discrimination of pediatric lower respiratory tract infections: implications for diagnostic study design

Accurate differentiation between viral and bacterial etiologies remains a major clinical challenge in pediatric lower respiratory tract infections (LRTIs), often leading to unnecessary antibiotic use. Host-response biomarkers such as myxovirus resistance protein A (MxA) reflect interferon-mediated antiviral responses and offer a biologically grounded diagnostic approach. This review aims to synthesize current evidence on the diagnostic performance of MxA in pediatric LRTIs and to derive methodological insights for the design of future prospective diagnostic studies.