Home self-collection of nasal swabs for diagnosis of acute respiratory virus infections in children with cystic fibrosis

Abstract

Background: Understanding the importance of respiratory viruses in children with cystic fibrosis (CF) has been limited because of challenges using clinic- or hospital-based diagnostic testing.We conducted a pilot study to assess feasibility of home self- (or parent-) collection of nasal swabs (NS). Methods: Cystic fibrosis patients aged 6-18 years with new respiratory illness participated. In clinic, a deep nasal flocked swab was collected by research staff and compared with an anterior foam NS obtained after instillation of saline spray. At home, up to 2 self-collections of paired foam NS (with and without saline) were collected and mailed for real-time polymerase chain reaction (PCR) testing. Results: Paired swabs were collected from 28 patients: 18 sets in clinic (deep nasal vs saline foam NS) and 43 sets at home (saline vs dry foam NS) with 9 (50%) and 35 (81%) virus detections, respectively. Home-collected NS were obtained closer to illness onset, with a mean difference in symptom days of -2.3 between home and clinic collections (95% confidence interval [CI] -3.5, -1.2; P < .001). Rhinovirus comprised 73% of virus detections; the difference in mean PCR cycle threshold values for rhinovirus between swabs collected at home versus clinic was -3.8 (95% CI -6.8, -0.9; P = .014), indicating significantly higher viral load for homecollected swabs. Conclusions: Home-collected foam NS had a higher positivity rate compared with clinic-collected swabs, likely because collection was closer to illness onset. Home self-collection is feasible and well tolerated for timely respiratory virus diagnosis and provides a novel approach for clinical diagnostics and surveillance of respiratory virus infections among CF patients.