- 著者
-
Takahiro Sanada
Tomoko Honda
Fumihiko Yasui
Kenzaburo Yamaji
Tsubasa Munakata
Naoki Yamamoto
Makoto Kurano
Yusuke Matsumoto
Risa Kohno
Sakiko Toyama
Yoshiro Kishi
Takuro Horibe
Yudai Kaneko
Mayumi Kakegawa
Kazushige Fukui
Takeshi Kawamura
Wang Daming
Chungen Qian
Fuzhen Xia
Fan He
Syudo Yamasaki
Atsushi Nishida
Takayuki Harada
Masahiko Higa
Yuko Tokunaga
Asako Takagi
Masanari Itokawa
Tatsuhiko Kodama
Michinori Kohara
- 出版者
- Japan Epidemiological Association
- 雑誌
- Journal of Epidemiology (ISSN:09175040)
- 巻号頁・発行日
- pp.JE20210324, (Released:2021-11-13)
- 参考文献数
- 26
- 被引用文献数
-
18
Background: Tokyo, the capital of Japan, is a densely populated city of >13 million people and thus at high risk of epidemic severe acute respiratory coronavirus 2 (SARS-CoV-2) infection. A serologic survey of anti–SARS-CoV-2 IgG would provide valuable data for assessing the city’s SARS-CoV-2 infection status. This cross-sectional study therefore estimated the anti–SARS-CoV-2 IgG seroprevalence in Tokyo.Methods: Leftover serum of 23,234 hospital visitors was tested for antibodies against SARS-CoV-2 using an iFlash 3000 chemiluminescence immunoassay analyzer (Shenzhen YHLO Biotech) with an iFlash–SARS-CoV-2 IgG kit (YHLO) and iFlash–SARS-CoV-2 IgG-S1 kit (YHLO). Serum samples with a positive result (≥10 AU/mL) in either of these assays were considered seropositive for anti–SARS-CoV-2 IgG. Participants were randomly selected from patients visiting 14 Tokyo hospitals between September 1, 2020, and March 31, 2021. No participants were diagnosed with coronavirus disease 2019 (COVID-19), and none exhibited COVID-19–related symptoms at the time of blood collection.Results: The overall anti–SARS-CoV-2 IgG seroprevalence among all participants was 1.83% (95% confidence interval [CI]: 1.66%-2.01%). The seroprevalence in March 2021, the most recent month of this study, was 2.70% (95% CI: 2.16%-3.34%). After adjusting for population age, sex, and region, the estimated seroprevalence in Tokyo was 3.40%, indicating that 470,778 individuals had a history of SARS-CoV-2 infection.Conclusions: The estimated number of individuals in Tokyo with a history of SARS-CoV-2 infection was 3.9-fold higher than the number of confirmed cases. Our study enhances understanding of the SARS-CoV-2 epidemic in Tokyo.