Evaluation of the ID NOW among symptomatic individuals during the Omicron wave

Abstract

Introduction. Starting in December, 2020, the ID NOW was implemented throughout the province of Alberta, Canada (population 4.4 million) in various settings. Gap statement. ID NOW's test performance with SARS-CoV-2 Omicron variant BA.1 is unknown. Aim. To assess the ID NOW performance among symptomatic individuals during the BA.1 Omicron wave and compare it to previous SARS-CoV-2 variant waves. Methodology. The ID NOW was assessed in two locations among symptomatic individuals: rural hospitals and community assessment centres (AC) during the period 5-18 January 2022. Starting 5 January, Omicron represented >95% of variants detected in our population. For every individual tested, two swabs were collected: one for ID NOW testing and the other for either reverse-transcriptase polymerase chain reaction (RT-PCR) confirmation of negative ID NOW results or for variant testing of positive ID NOW results. Results. A total of 3041 paired samples were analysed (1139 RT-PCR positive). From this, 1873 samples were from 42 COVID-19 AC and 1168 from 69 rural hospitals. ID NOW sensitivity for symptomatic individuals presenting to community AC and rural hospitals was 96.0% [95% confidence interval (CI) 94.5-97.3%, n=830 RT-PCR positive], and 91.6% (95% CI 87.9-94.4%, n=309 RT-PCR positive), respectively. SARS-CoV-2 positivity rate was very high for both populations (44.3% at AC, 26.5% in hospital). Conclusions. Sensitivity of ID NOW SARS-CoV-2, compared to RT-PCR, is very high during the BA.1 Omicron wave, and is significantly higher when compared to previous SARS-CoV-2 variant waves.