The acceptability and validity of self-collected nasal swabs for detection of influenza virus infection among older adults in Thailand

Abstract

Background: Self-collection of nasal swabs could improve the timeliness of influenza virus detection in older adults.

Objectives: Measure the acceptability, adequacy, timeliness, and validity of self-collected nasal swabs among adults >65 years in Thailand.

Methods: Our evaluation consisted of two parts: a one-month study among randomly selected, community-dwelling older adults to simulate community-based surveillance for acute respiratory infections (ARI); and a clinic study of older adults with ARI to evaluate the sensitivity and specificity of self-collected nasal swabs for influenza virus infection compared with healthcare worker (HCW)-collected nasal and nasopharyngeal swabs.

Results: In the community study, 24% of participants experienced an ARI during the observation period. All (100%) participants with an ARI self-collected nasal swabs within 72 hours of symptom onset of which 92% were considered adequate samples. In the clinic study, 45% of patients with ARI presented within 72 hours of symptom onset. The sensitivity of self-collected nasal swabs for detection of influenza virus infection was 78% (95% CI 40-97) compared to nasopharyngeal and 88% (95% CI 47-100) compared to nasal swabs collected by HCWs. Specificity was 100% (95% CI 97-100) compared to both methods. Self-collection of nasal swabs was found acceptable by 99% of participants in both studies.

Conclusions: Self-collection of nasal swabs was acceptable to older adults in Thailand who were able to take adequate samples. Self-collection of nasal swabs may improve the timeliness of sample collection but lower sensitivity will need to be considered.

Keywords: Thailand; elderly; influenza; nasal swab; self-collection; sensitivity.