Epidemiology and Persistence of Human Rhinovirus Infections in Childcare
Methods: Children ages 5 weeks to 30 months were prospectively enrolled from three large childcare centers located in Fort Lewis, WA, USA. Nasopharyngeal swabs were collected at enrollment and at onset and weekly during respiratory illness episodes until symptoms resolved. Nasal samples were tested by PCR for HRV and other respiratory viruses and HRV genotype was determined by sequencing the 5’ non-coding region. Extended shedding was defined as consecutive positive swabs at least 7 days apart.
Results: During the study period, 225 children were enrolled. A total of 127 children provided an asymptomatic nasal swab at enrollment, with 52 (41%) having HRV present. HRV was detected during 223 out of 455 prospectively-captured illnesses; 123 children had HRV detected during at least one illness. HRV detection persisted for at least 7 days in 28% of all HRV illnesses (n=62; mean duration 16 days among those with extended shedding). Only 5 of 62 illnesses with extended shedding (8%) had multiple HRV genotype groups identified in different swabs. Respiratory illness symptoms, including fever and cough, were similar regardless of the duration of shedding. HRV illnesses accompanied by other coinfecting respiratory viruses were more likely to have extended shedding compared to illnesses with HRV alone (mean 7 versus 1 days, respectively; p<0.001). Children under 9 months of age shed for a mean of 4 days longer than older children (p=0.03).
Conclusion: We found that extended shedding occurred in over a third of all incident HRV infections. Risk factors for HRV extended shedding include young age and respiratory viral coinfections. In most cases, shedding was not due to subsequent infection with multiple HRV genotypes. This extended shedding may provide an explanation, especially in young children, for the high rates of asymptomatic detection of rhinovirus that has been previously reported.
E. T. Martin,
E. Martin, None
H. Y. Chu, None
M. Fairchok, None
J. Kuypers, None
J. A. Englund, Gilead: Consultant and Investigator, Consulting fee and Research support
Chimerix: Investigator, Research support
Roche: Investigator, Research support
GlaxoSmithKline: Consultant, Investigator and Member, DSMB (DataSafety Monitoring Board), Consulting fee, Payment for DSMB participation and Research support
Ansun Biopharma: Investigator, Research support
MedImmune: Grant Investigator, Research support
Seattle Children's Hospital: Investigator, Research support