1. Age-Stratified Seroprevalence of SARS-CoV-2 Antibodies before and during the Vaccination Era, Japan, February 2020–March 2022
- Author
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Seiya Yamayoshi, Kiyoko Iwatsuki-Horimoto, Moe Okuda, Michiko Ujie, Atsuhiro Yasuhara, Jurika Murakami, Calvin Duong, Taiki Hamabata, Mutsumi Ito, Shiho Chiba, Ryo Kobayashi, Satoshi Takahashi, Keiko Mitamura, Masao Hagihara, Akimichi Shibata, Yoshifumi Uwamino, Naoki Hasegawa, Toshiaki Ebina, Akihiko Izumi, Hideaki Kato, Hideaki Nakajima, Norio Sugaya, Yuki Seki, Asef Iqbal, Isamu Kamimaki, Masahiko Yamazaki, Yoshihiro Kawaoka, and Yuki Furuse
- Subjects
COVID-19 ,coronavirus disease ,SARS-CoV-2 ,severe acute respiratory syndrome coronavirus 2 ,viruses ,respiratory infections ,Medicine ,Infectious and parasitic diseases ,RC109-216 - Abstract
Japan has reported a relatively small number of COVID-19 cases. Because not all infected persons receive diagnostic tests for COVID-19, the reported number must be lower than the actual number of infections. We assessed SARS-CoV-2 seroprevalence by analyzing >60,000 samples collected in Japan (Tokyo Metropolitan Area and Hokkaido Prefecture) during February 2020–March 2022. The results showed that ≈3.8% of the population had become seropositive by January 2021. The seroprevalence increased with the administration of vaccinations; however, among the elderly, seroprevalence was not as high as the vaccination rate. Among children, who were not eligible for vaccination, infection was spread during the epidemic waves caused by the SARS-CoV-2 Delta and Omicron variants. Nevertheless, seroprevalence for unvaccinated children
- Published
- 2022
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