Duration of Rhinovirus Shedding in the Upper Respiratory Tract in the First Year of Life

Abstract

WHAT'S KNOWN ON THIS SUBJECT: Rhinoviruses are commonly detected in both acutely ill and asymptomatic infants and children. The finding may represent new infection or prolonged presence of rhinovirus RNA in the respiratory tract. WHAT THIS STUDY ADDS:In young, otherwise healthy infants, shedding of RNA from the same rhinovirus strain rarely persisted longer than 30 days. abstract BACKGROUND: Current molecular diagnostic methods have detected rhinovirus RNA in a high proportion of asymptomatic infants and children, raising the question of the clinical significance of these findings. This study investigates the prevalence of prolonged rhinovirus RNA presence in the upper respiratory tract of infants during the first year of life. METHODS:In a longitudinal study, infants were followed from birth up to 12 months. Nasopharyngeal specimens were collected monthly (months 1-6 and month 9) and during an upper respiratory infection. Rhinoviruses were detected by quantitative reverse-transcription polymerase chain reaction. Presence of repeated rhinovirus RNA was evaluated by nucleotide sequence analysis. RESULTS:A total of 2153 specimens from 362 infants were studied; 341 distinct rhinovirus infections in 216 infants were identified. Follow-up specimens were available within 30 days for 179 infections, creating the sample set to assess prolonged rhinovirus presence. Of the 179 infections, 46 involved the detection of the same rhinovirus strain in repeated specimens, including 8 events of prolonged presence of the same strain (detected in specimens collected .30 days apart), representing 4.5% of the evaluable rhinovirus infections. There were 26 events in which a rhinovirus strain was replaced by a different strain within a 30-day interval, representing 14.5% of the 179 infections. CONCLUSIONS:Although rhinovirus infections are common in healthy infants, prolonged presence of rhinovirus RNA in the respiratory tract after an upper respiratory infection was uncommon (,5%). Detection of rhinovirus RNA in an infant most likely represents an infection within a 30-day period. Dr Loeffelholz co-conceptualized and co-designed the study and wrote the initial manuscript; Dr Trujillo coordinated data collection; Dr Pyles conceptualized and supervised molecular virology studies and reviewed and revised the manuscript; Mr Miller performed molecular virology studies and provided interpretation of the data for inclusion in the manuscript; Dr Alvarez-Fernandez supervised data collection; Dr Pong performed molecular virology studies and performed data collection and analysis; Dr Chonmaitree conceptualized and designed the study, provided overall study supervision, and revised the manuscript; and all authors approved the final manuscript as submitted and agree to be accountable for all aspects of the work. 4,5 A study in adult volunteers showed that cultivatable rhinoviruses were routinely recovered for ∼2 weeks after infection. 6 Recurrent rhinovirus infection has been described in patients with asthma 7 and in those at risk of developing...

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