SARS-CoV-2 screening test for Japanese returnees from Wuhan, China, January 2020

Kutsuna, Satoshi; Suzuki, Tadaki; Hayakawa, Kayoko; Tsuzuki, Shinya; Asai, Yusuke; Suzuki, Tetsuya; Ide, Satoshi; Nakamura, Keiji; Moriyama, Yuki; Kinoshita, Noriko; Hosokawa, Naoto; Osawa, Ryosuke; Yamamuro, Ryosuke; Akiyama, Yutaro; Miyazato, Yusuke; Nomoto, Hidetoshi; Nakamoto, Takato; Ota, Masayuki; Saito, Sho; Ishikane, Masahiro; Morioka, Shinichiro; Yamamoto, Kei; Ujiie, Mugen; Terada, Mari; Nakamura-Uchiyama, Fukumi; Sahara, Toshinori; Sano, Masahiro; Imamura, Akifumi; Sekiya, Noritaka; Fukushima, Kazuaki; Kawana, Akihiko; Fujikura, Yuji; Sano, Tomoya; Suematsu, Ryohei; Sakamoto, Naoya; Nagata, Kaoru; Kato, Tomoyuki; Katano, Harutaka; Wakita, Takaji; Sugiyama, Haruhito; Kokudo, Norihiro; Ohmagari, Norio

BACKGROUND: Severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2) was found to be the causative microorganism of coronavirus disease 2019 (COVID-19), which started to spread in Wuhan, China. This study was to evaluate the effectiveness of questionnaire, symptoms-based screening, and PCR screening of returnees from COVID-19 endemic areas on a chartered flight, to examine the proportion of infected persons and the proportion of asymptomatic persons among infected persons who returned from Wuhan. METHODS: A retrospective cohort study was done in seven tertiary medical institutions in Japan. A total of 566 Japanese who returned from Wuhan participated in the study. RESULTS: Overall, 11 of the 566 passengers had a positive SARS-CoV-2 PCR result for pharyngeal swabs and six were asymptomatic. Only fever differed between SARS-CoV-2-positive and -negative individuals (p < 0.043). Six of the eleven PCR-positive individuals were asymptomatic and four remained positive on day 10 and One asymptomatic person tested positive up to day 27. Two of the eleven were negative on the first PCR test and positive on the second. CONCLUSIONS: Our results will be important insights on screening returnees from locked down cities, as well as important data on the proportion of asymptomatic individuals infected with SARS-CoV-2. A 13-day observation period and a second round of PCR may be effective to screen patients, including asymptomatic infections.