Rhinovirus Disease in Children Seeking Care in a Tertiary Pediatric Emergency Department

Background. Rhinovirus is the most common cause of viral respiratory tract infections in children. Virologicpredictors of lower respiratory tract infection (LRTI), such as viral load and the presence of another respiratoryvirus (coinfection), are not well characterized in pediatric outpatients.Methods. Mid-nasal turbinate samples were collected from children presenting for care to the SeattleChildren’s Hospital emergency department (ED) or urgent care with a symptomatic respiratory infectionbetween December 2011 and May 2013. A subset of samples was tested for rhinovirus viral load by real-timepolymerase chain reaction. Clinical data were collected by chart reviews. Multivariate logistic regression wasused to evaluate the relationship between viral load and coinfection and the risk for LRTI.Results. Rhinovirus wasthe most frequent respiratory virus detected in children younger than 3 years. Of 445patients with rhinovirus infection, 262 (58.9%) had LRTIs, 231 (51.9%) required hospital admission and 52(22.5%)werehospitalizedfor3 daysorlonger.Childrenwithnocomorbiditiesaccountedfor142(54%)of262rhinovirus LRTIs. Higher viral load was significantly associated with LRTI among illness episodes withrhinovirus alone (OR, 2.11; 95% confidence interval [CI], 1.24–3.58). Coinfection increased the risk of LRTI(OR, 1.83; 95% CI, 1.01–3.32).Conclusions. Rhinovirus was the most common pathogen detected among symptomatic young children in apediatric ED who had respiratory viral testing performed, with the majority requiring hospitalization. Higherrhinovirus viral load and coinfection increased disease severity. Virologic data may assist clinical decisionmaking for children with rhinovirus infections in the pediatric ED.Key words. rhinovirus; viral load; disease severity; coinfection; emergency department.Human rhinovirus (HRV) is the most common etiology ofviral upper respiratory tract infections (URTIs) in childrenworldwide and causes primarily mild self-limited infec-tions with rhinorrhea, cough, sore throat, and nasal con-gestion [1, 2]. HRV also causes lower respiratory tractinfections (LRTIs), particularly in young infants, theelderly, and patients with immunocompromising condi-tionssuchasasthma,malignancy,cysticfibrosis,orchronicobstructive pulmonary disease [3, 4]. Among outpatientspresenting forevaluation in the clinic setting, HRV is asso-ciated with a burden of disease similar to that of influenza[5]. However, frequent detection of HRV among asymp-tomatic children or in the presence of respiratory viralcoinfections, such as respiratory syncytial virus (RSV),makes it difficult to define its true etiologic role [4,6,7].Recentimprovementsinmoleculartechniques,includingreal-time quantitative polymerase chain reaction (qPCR)assays, have permitted increased identification of HRV asthecause ofrespiratorytractinfections [8].Anunderstand-ing of how to interpret virologic data is increasingly rele-vant to outpatient clinical care, because rapid multiplexPCR assays are used for the point-of-care diagnosis of re-spiratory viruses in emergency department (ED) and ur-gent care (UC) settings [9, 10]. Rapid tests can provideresults, including a semiquantitative measure of viral load(VL), in lessthan 1 hour [11].Rapid diagnosis of influenzain a pediatric ED has been shown to decrease antiviral use,