The development of COPMAN-Air: A highly sensitive method for detecting SARS-CoV-2 in air

Several studies have successfully detected SARS-CoV-2 in air samples; however, in most of these, the focus was on validating the air collection method, and there was no report on the development of a virus-detection method. In this study, to detect viruses in air samples more sensitively than conventional detection methods, we applied COPMAN, a highly sensitive virus-detection method using wastewater samples, to air samples to develop COPMAN-Air. Briefly, with this method, the extremely low amount of viral RNA in air samples is efficiently detected via three reaction steps: RT, preamplification, and qPCR, as with COPMAN. We evaluated COPMAN-Air using samples from a fever clinic for COVID-19 patients. COPMAN-Air demonstrated a higher detection rate of viral RNA compared to conventional methods: 22 (95.7%) vs. 14 (60.9%) out of 23 samples. Additionally, a positive correlation (r=0.70) was found between the amount of viral RNA detected by COPMAN-Air and the number of confirmed COVID-19 cases, suggesting that COPMAN-Air could estimate the number of SARS-CoV-2-positive individuals in a given space based on the quantitative values of SARS-CoV-2 RNA in air samples. Surveillance systems for pathogens in the air using COPMAN-Air are expected to be valuable for assessing the number of infected individuals and for the implementation of public health measures.