Detection of respiratory syncytial virus and rhinovirus in healthy infants

BACKGROUND: Despite the research importance of rhinovirus detection in asymptomatic healthy infants, the literature remains sparse. OBJECTIVE: To investigate the prevalence of respiratory syncytial virus (RSV) and rhinovirus (and its species). METHODS: We conducted a cross-sectional study of 110 healthy, non-hospitalized infants without acute illness at an academic medical center from November 2013 through May 2014. We tested nasal swab specimens by using polymerase chain reaction and genetic sequencing. RESULTS: Overall, the median age was 3.8 months (IQR 2.0-5.1 months), 56 % were male, and 90% were born >37 weeks. RSV was detected in nasal swabs from infants (1.8%). By contrast, rhinovirus was detected in nasal swabs from 16 infants (14.5%). Molecular typing assay revealed rhinovirus species: six rhinovirus-A (5.5%), one rhinovirus-B (0.9%), eight rhinovirus-C (7.3%), and one untypeable (0.9%). CONCLUSIONS: In this cross-sectional study of healthy, community-based infants, RSV was rare (<2%) in nasal swabs, while rhinovirus was detected in 14.5% with a predominance of rhinovirus-A and -C. These finding are important for understanding the clinical significance of rhinovirus detection among infants hospitalized for bronchiolitis.