SELF-COLLECTION IN CYMOL FOR DIAGNOSIS AND SURVEILLANCE OF UPPER RESPIRATORY INFECTIONS IN UNIVERSITY STUDENTS

Abstract

Background:

CyMol (Copan) is an alternative sample collection system that may be beneficial during a pandemic because of its ability to render a virus non-infectious and stabilize the nucleic acid for molecular testing. Objective: To evaluate self-collected nasal flocked swabs in CyMol for use in routine diagnosis and surveillance.

Methods:

University students (age ≥17) that presented within 48 hours of onset to a Campus Health Center with symptoms of URI (nasal congestion, pharyngitis, fever, cough, headache, and fatigue) were invited to provide a self-collected and a staff-collected nasal flocked mid-turbinate swab from opposite nostrils. Parallel nasal swabs were collected over a 17 week period from January to April 2009 and placed in computer randomized order, into either CyMol or UTM-RT prior to transport to the laboratory. The nasal swab samples were extracted by easyMAG (bioMérieux) and the purified nucleic acid tested in the Luminex x-TagTM RVP assay. The study was approved by the ethics board, and all subjects provided written, informed consent.

Results:

A respiratory virus was detected by RVP in 41 of the 73 students (56.2%) presenting with symptoms of URI. RVP identified 9 influenza A (six H1, three H3), 8 influenza B, 5 entero/rhinovirus, 15 coronaviruses (eight 229E, three NL63 and four OC43), 2 metapneumovirus (MPV), 1 adenovirus and 1 respiratory syncytial virus (RSV). Of the 41 RVP-positive students, 29 had concordant positive results for the same virus in both the CyMol and UTM® collection systems, 5 were positive only in CyMol, 7 only in UTM®, and 32 were negative with both collection systems. Swabs taken in UTM® were positive in 36/41 (87.8%), while those taken in CyMol were positive in 34/41 (82.9%, P=0.56, McNemar test for the paired comparison). For the comparison of the two transport media, raw agreement was 61/73 (83.6%) and kappa (agreement beyond chance) was 0.67 (95% CI: 0.50, 0.84). To evaluate self-collected versus staff-collected, two nasal mid-turbinate swabs were taken per student. Of the 41 RVP-positive students, 33 (80.5%) were positive in self-collected swabs and 37 (90.2%) were positive in staff-collected swabs, (P=0.25 for the difference, McNemar test). For the comparison of self- and staff-collected swabs, raw agreement was 61/73 (83.6%) and kappa was 0.67 (95% CI: 0.50, 0.84).

Conclusions:

In this blinded, randomized comparison of CyMol and UTM, the two collection systems were equivalent for PCR testing. Our study also provided further validation for self-collected nasal swabs as an alternative to staff-collected nasal swabs. Self-collected nasal swabs combined with a highly-sensitive multiplex PCR yielded a respiratory virus diagnosis in over 50% of students. Self-collection in CyMol is an effective approach for diagnosis and surveillance of URI.