tetano
Editor, Senior Moderator
Jpn J Infect Dis
. 2021 Mar 31.
doi: 10.7883/yoken.JJID.2020.1073. Online ahead of print.
Epidemiology of coronavirus disease 2019 in Yamagata Prefecture, Japan, January-May 2020: The importance of retrospective contact tracing
Junji Seto[SUP] 1 [/SUP], Yoko Aoki[SUP] 1 [/SUP], Kenichi Komabayashi[SUP] 1 [/SUP], Yoko Ikeda[SUP] 1 [/SUP], Mika Sampei[SUP] 1 [/SUP], Naomi Ogawa[SUP] 1 [/SUP], Yumiko Uchiumi[SUP] 2 [/SUP], Shunji Fujii[SUP] 2 [/SUP], Masami Chiba[SUP] 3 [/SUP], Emiko Suzuki[SUP] 3 [/SUP], Tatsuya Takahashi[SUP] 4 [/SUP], Keiko Yamada[SUP] 4 [/SUP], Yoshiko Otani[SUP] 5 [/SUP], Yoshihiro Ashino[SUP] 5 [/SUP], Kyoko Araki[SUP] 6 [/SUP], Takeo Kato[SUP] 6 [/SUP], Hitoshi Ishikawa[SUP] 5 7 [/SUP], Tatsuya Ikeda[SUP] 1 8 [/SUP], Hideaki Abe[SUP] 8 [/SUP], Tadayuki Ahiko[SUP] 1 8 [/SUP], Katsumi Mizuta[SUP] 1 [/SUP]
Affiliations
Abstract
Public health interventions have served an important role in controlling coronavirus disease 2019 (COVID-19), a rapidly spreading infectious disease. To contribute to future COVID-19 countermeasures, we aimed at verifying the results of countermeasures achieved by public health centers (PHCs) against the first wave of COVID-19 in Yamagata Prefecture, Japan. During January-May 2020, 1,253 patients suspected of SARS-CoV-2 infection were invited for testing. Simultaneously, based on retrospective contact tracings, PHCs investigated the infection sources and transmission routes of laboratory-confirmed COVID-19 cases and tested 928 contacts. Consequently, 69 cases were confirmed during March 31 - May 4, 58 (84.1%; 95% confidence interval 75.5-92.7) of whom were found from contacts. The spread of infection was triggered by cases harboring epidemiological links outside of Yamagata. Then, the number of cases increased rapidly. However, PHCs identified epidemiological links in 61 (88.4%; 95% confidence interval 80.8-96.0) of the 69 cases and transmission chains up to the fifth generation. Finally, the spread of infection ended after approximately one month. Our results indicate that the identification of infection sources and active case finding from contacts based on retrospective contact tracing was likely to be an effective strategy to end the first wave of COVID-19 in Yamagata.
Keywords: SARS-CoV-2; close contact; cluster-based approach; infection source; testing.
. 2021 Mar 31.
doi: 10.7883/yoken.JJID.2020.1073. Online ahead of print.
Epidemiology of coronavirus disease 2019 in Yamagata Prefecture, Japan, January-May 2020: The importance of retrospective contact tracing
Junji Seto[SUP] 1 [/SUP], Yoko Aoki[SUP] 1 [/SUP], Kenichi Komabayashi[SUP] 1 [/SUP], Yoko Ikeda[SUP] 1 [/SUP], Mika Sampei[SUP] 1 [/SUP], Naomi Ogawa[SUP] 1 [/SUP], Yumiko Uchiumi[SUP] 2 [/SUP], Shunji Fujii[SUP] 2 [/SUP], Masami Chiba[SUP] 3 [/SUP], Emiko Suzuki[SUP] 3 [/SUP], Tatsuya Takahashi[SUP] 4 [/SUP], Keiko Yamada[SUP] 4 [/SUP], Yoshiko Otani[SUP] 5 [/SUP], Yoshihiro Ashino[SUP] 5 [/SUP], Kyoko Araki[SUP] 6 [/SUP], Takeo Kato[SUP] 6 [/SUP], Hitoshi Ishikawa[SUP] 5 7 [/SUP], Tatsuya Ikeda[SUP] 1 8 [/SUP], Hideaki Abe[SUP] 8 [/SUP], Tadayuki Ahiko[SUP] 1 8 [/SUP], Katsumi Mizuta[SUP] 1 [/SUP]
Affiliations
- PMID: 33790065
- DOI: 10.7883/yoken.JJID.2020.1073
Abstract
Public health interventions have served an important role in controlling coronavirus disease 2019 (COVID-19), a rapidly spreading infectious disease. To contribute to future COVID-19 countermeasures, we aimed at verifying the results of countermeasures achieved by public health centers (PHCs) against the first wave of COVID-19 in Yamagata Prefecture, Japan. During January-May 2020, 1,253 patients suspected of SARS-CoV-2 infection were invited for testing. Simultaneously, based on retrospective contact tracings, PHCs investigated the infection sources and transmission routes of laboratory-confirmed COVID-19 cases and tested 928 contacts. Consequently, 69 cases were confirmed during March 31 - May 4, 58 (84.1%; 95% confidence interval 75.5-92.7) of whom were found from contacts. The spread of infection was triggered by cases harboring epidemiological links outside of Yamagata. Then, the number of cases increased rapidly. However, PHCs identified epidemiological links in 61 (88.4%; 95% confidence interval 80.8-96.0) of the 69 cases and transmission chains up to the fifth generation. Finally, the spread of infection ended after approximately one month. Our results indicate that the identification of infection sources and active case finding from contacts based on retrospective contact tracing was likely to be an effective strategy to end the first wave of COVID-19 in Yamagata.
Keywords: SARS-CoV-2; close contact; cluster-based approach; infection source; testing.