Participant self-collected versus research coordinator-collected nasal swabs for respiratory viral surveillance following influenza-like illness.

BackgroundUnsupervised, self-collected nasal swabs (SCNS) are a convenient alternative to collection by health-care workers for influenza-like illness (ILI) surveillance. We compared viral respiratory pathogen detection in paired SCNS versus research coordinator-collected nasal swabs (CCNS).MethodsAdult Military Health System beneficiaries were enrolled in a prospective influenza vaccine effectiveness trial. Following vaccination, participants were contacted weekly to ascertain ILI symptoms. In the event of an ILI, participants completed a symptom diary, a SCNS, and were offered a visit for CCNS. We evaluated respiratory pathogen detection by PCR, concordance between paired swabs (Cohen's Kappa statistic), and the impact of the timing (days post symptom onset [DPSO]) of collection on detection.Results3,357 ILIs were reported during the study period and paired (SCNS and CCNS) swabs were obtained during 1,048 ILIs. Among the paired swabs, SCNS were generally collected earlier than CCNS (median DPSO: 3.0 versus CCNS: 7.0; p