Evaluating Specimen Quality and Results from a Community-Wide, Home-Based Respiratory Surveillance Study

Abstract

While influenza and other respiratory pathogens cause significant morbidity and mortality, the community-based burden of these infections remains incompletely understood. The development of novel methods to detect respiratory infections is essential for mitigating epidemics and developing pandemic-preparedness infrastructure. From October 2019 to March 2020, we conducted a home-based cross-sectional study in the greater Seattle, WA, area, utilizing electronic consent and data collection instruments. Participants received nasal swab collection kits via rapid delivery within 24 hours of self-reporting respiratory symptoms. Samples were returned to the laboratory and were screened for 26 respiratory pathogens and a housekeeping gene. Participant data were recorded via online survey at the time of sample collection and 1 week later. Of the 4,572 consented participants, 4,359 (95.3%) received a home swab kit and 3,648 (83.7%) returned a nasal specimen for respiratory pathogen screening. The 3,638 testable samples had a mean RNase P relative cycle threshold (C_rt ) value of 19.0 (SD, 3.4), and 1,232 (33.9%) samples had positive results for one or more pathogens, including 645 (17.7%) influenza-positive specimens. Among the testable samples, the median time between shipment of the home swab kit and completion of laboratory testing was 8.0 days (interquartile range [IQR], 7.0 to 14.0). A single adverse event occurred and did not cause long-term effects or require medical attention. Home-based surveillance using online participant enrollment and specimen self-collection is a safe and feasible method for community-level monitoring of influenza and other respiratory pathogens, which can readily be adapted for use during pandemics.

Keywords: influenza; nasal swab; pandemic preparedness; rapid diagnosis; respiratory pathogens.

FIG 1

Study procedure completion rates. Mail packaging errors included a damaged box, a different box used than the one provided, an improperly closed box, or an improperly used specimen transport bag or lack thereof. Sample tube use errors included damaged or broken UTM tube, an absent swab, or leakage. Sample tube labeling errors included a missing written full name or date of collection on the UTM tube.

FIG 2

Pathogens detected in participants over time from 16 October 2019 to 9 March 2020.

FIG 3

Median delivery times of home swab kits to participants by distance from study laboratory (n = 2,398).

FIG 4

Average RNase P C_rt values by discomfort of and confidence in home swab collection. Participants (n = 1,796) who enrolled from 6 January 2020 to 9 March 2020 were asked to rate their confidence in the correct completion of the home swab (not confidence at all, somewhat confident, or very confident) and their discomfort in the collection of the home swab (no discomfort, mild discomfort, or strong discomfort).