RSV-infected children with mixed infections: clinical features and early predictive indicators of codetection with Streptococcus pneumoniae and Haemophilus influenzae

BackgroundSince the COVID-19 pandemic, the incidence of respiratory syncytial virus (RSV) infections has significantly increased, and bacterial codetection further exacerbates the disease burden. This study aims to compare the clinical characteristics, laboratory results, and prognostic differences in children with RSV infection who are codetected with Streptococcus pneumoniae and Haemophilus influenzae, and to identify early predictive markers for such codetections.MethodsIn this single-center retrospective study, we collected data from 1,601 children hospitalized with RSV infection at Luoyang Maternal and Child Health Hospital, Henan Province, between January 2023 and March 2025. Children were divided into three groups: non-bacterial codetection, S. pneumoniae codetection, and H. influenzae codetection. We compared demographic characteristics, clinical features, laboratory findings, and prognosis. Logistic regression identified risk factors for codetection of S. pneumoniae and H. influenzae.ResultsA history of wheezing increased the likelihood of codetection with both bacteria. Children with S. pneumoniae codetection were more likely to present with fever, whereas those with H. influenzae codetection were more prone to wheezing and respiratory distress. The presence of extrapulmonary manifestations was a significant common factor for both codetections. Regarding laboratory markers, children with codetection of S. pneumoniae showed significantly elevated levels of WBC, NLR, CRP, PCT, and IL-6. For those codetected with H. influenzae, WBC, NLR, CRP, PCT, IL-6, PLT, and D-dimer levels were all significantly increased. Children with either bacterial codetection required significantly more respiratory support, had higher PICU admission rates, and experienced longer hospital stays. A history of wheezing and elevated IL-6 levels were associated with a higher likelihood of S. pneumoniae codetection, while younger age and higher levels of WBC, CRP, and IL-6 were predictive of H. influenzae codetection.ConclusionsCompared with children with RSV infection alone, those with codetection of S. pneumoniae or H. influenzae exhibit significantly elevated inflammatory markers, especially IL-6. These children are more likely to require PICU admission and respiratory support, and to experience longer hospital stays.