Viral load dynamics and clinical disease severity in infants with respiratory syncytial virus infection

Abstract

Background. Te association between respiratory syncytial virus (RSV) loads and clinical outcomes in children remains to be defned. In most studies, viral loads (VL) were evaluated in hospitalized children and at a single time-point. We investigated the relationship between VLs and disease severity in both outpatients and inpatients with RSV infection. Methods. We enrolled previously healthy children with RSV infection. Disease severity was defned by level of care (outpatients vs ward vs pediatric intensive care unit [PICU]), and a clinical disease severity score (CDSS). Nasopharyngeal VLs by polymerase chain reaction and CDSS were measured at enrollment and daily in inpatients. VL decay according to disease severity was analyzed using linear mixed modeling. Results. From February 2015 to March 2017, we enrolled 150 infants: 39 outpatients and 111 inpatients. VLs were higher in outpatients than in age-matched inpatients. Among inpatients, initial VLs were comparable in ward and PICU patients, and preceded the peak CDSS. However, afer excluding infants treated with steroids, those hospitalized in the ward had higher VLs than infants requiring PICU care (P