Predictors of SARS-CoV-2 Positivity Based on RT-PCR Swab Tests at a Drive-Through Outpatient Clinic for COVID-19 Screening in Japan
Tadashi Ishii, Shigeki Kushimoto, Yukio Katori, Shigeo Kure, Kaoru Igarashi, Motoo Fujita, Shin Takayama, Michiaki Abe, Junichi Tanaka, Akiko Kikuchi, Yoshiko Abe, Hiroyuki Imai, Yohei Inaba, Yoko Iwamatsu‐Kobayashi, Takashi Nishioka, Ko Onodera, Tetsuya Akaishi
Abstract
In response to the COVID-19 pandemic caused by SARS-CoV-2 in 2020, we conducted drive-through nasopharyngeal swab testing for COVID-19 in Sendai city, Japan, since April 2020. All tested individuals were judged in advance by public health centers for the necessity of undergoing the test with possible contact history and/or symptoms suggestive of COVID-19. In this study, to identify the predictors of SARS-CoV-2 test positivity for more efficient and evidenced selection of suspected individuals, we enrolled 3,540 consecutive individuals, tested in the first 7 months of the testing program, with data regarding to the history of close contact with COVID-19 patients, including those involved in cluster outbreaks. This cohort included 284 foreign students (257 males and 27 females) from a vocational school involved in the largest cluster outbreak in the area. Close contact history was present in 952 (26.9%) of the participants. The reverse transcription-polymerase chain reaction (RT-PCR) test results showed that 164 participants (4.6%) were positive and 3,376 participants (95.4%) were negative for the SARS-CoV-2 nucleocapsid gene (N2). In the univariate and multivariate analyses, history of close contact with COVID-19 patients, higher age, cough symptoms, and non-native ethnicity were predictors for SARS-CoV-2 test positivity. However, the significance of age and foreign nationality disappeared or declined upon excluding the foreign students from the aforementioned largest cluster outbreak. In conclusion, a history of close contact with COVID-19 patients and the presence of cough symptoms are significant predictors of SARS-CoV-2 test positivity.