Date created: | Last Updated:

Category: Project

Description: OBJECTIVE Queensland’s Novel Coronavirus (SARS-CoV-2) suppression program has been relatively successful. Initially, it involved extensive community testing and repeat sampling of positive individuals for release from isolation. This enabled study of several characteristics, including persistence of detectable virus and how apparent viral clearance rates varied by age and sex. DESIGN We conducted an exploratory analysis of Queensland Pathology SARS-CoV-2 reverse transcriptase polymerase chain reaction (RT-PCR) test results. Kaplan Meier analyses were used to estimate median time to apparent viral clearance, and Cox regression to explore the effects of sex and age. SETTING AND PARTICIPANTS Individuals tested for presence of SARS-CoV-2 in the upper respiratory tract between January 19 and June 4, 2020. OUTCOME MEASURES Presence of viral RNA detected by RT-PCR. RESULTS We analyzed 97,476 individuals. Median age was 41y (range <1-105y), and 57.2% (95% CI 57.2, 57.2) were female. In total, 958 (0.98%; 95% CI 0.92,1.05) tested positive for SARS-CoV-2. Positivity rates were lower in regional areas than cities, in females (OR 0.80, 95% CI 0.70, 0.91), and in those aged 16y and below (p<0.01, test for trend). Of the 958 positive individuals, 243 had two or more (max 17) additional tests, and 92% (95% CI 88.1, 95.2) remained positive after 10 days (max 76 days) after the initial result. Median time to apparent viral clearance was longer in those 65y and over compared to those under 65y (29 v 43 days, HR 1.85; 95% CI 1.17, 2.90), and was unaffected by sex (HR 0.93; 95% CI 0.66, 1.30). CONCLUSIONS Females and those 16y and under were less likely to test positive for SARS-CoV-2. Detectable RNA may persist for long periods, negating the value of repeat testing for declaring individuals free of infection. Viral clearance rates appear lower in those over 65y of age compared with younger individuals.