Regional Difference in Seroprevalence of SARS-CoV-2 in Tokyo: Results from the community point-of-care antibody testing (preprint)

The serosurvey is an alternative way to know the magnitude of the population infected by coronavirus disease 2019 (COVID-19) since the expansion of capacity of the polymerase chain reaction (PCR) to detect the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was delayed. We herein report seroprevalence of COVID-19 accessed in the two community clinics in Tokyo. The point-of-care immunodiagnostic test was implemented to detect the SARS-CoV-2 specific IgG antibody in the peripheral capillary blood. The overall positive percentage of SARS-CoV-2 IgG antibody is 3.83% (95% confidence interval: 2.76-5.16) for the entire cohort (n =1,071). The central Tokyo of 23 special wards exhibited a significantly higher prevalence compared to the other area of Tokyo (p =0.02, 4.68% [95%CI: 3.08-6.79] versus 1.83 [0.68-3.95] in central and suburban Tokyo, respectively). The seroprevalence of the cohort surveyed in this study is low for herd immunity, which suggests the need for robust disease control and prevention. A community-based approach, rather than state or prefectural levels, is of importance to figure out profiles of the SARS-COV-2 outbreak.

Preliminary Results of Seroprevalence of SARS-CoV-2 at Community Clinics in Tokyo (preprint)

Serological evaluation with SARS-CoV-2 specific IgG antibody will be an alternative way to know the pandemic of novel coronavirus disease (COVID-19) if the capacity for diagnostic PCR test is limited. The point-of-care test to detect SARS-CoV-2 specific IgG antibody in peripheral blood (n =202) was performed in two community clinics in Tokyo, Japan. The overall positive rate of SRAS-CoV-2 IgG antibody was 5.9% (95% confidence interval[CI]: 3.1-10.1). Higher rate was observed for healthcare workers (n =55, 9.1 [3.0-20.0]). The limitation on antibody tests includes low sensitivity and potent cross-reactivity with the previous coronavirus. Robust healthcare policy to efficiently monitor COVID-19 spread is warranted in Tokyo.

Prevalence of novel coronavirus pneumonia in the early stage of transmission and responding strategies in Japan / 上海预防医学

Novel coronavirus pneumonia disease (COVID-19) caused by SARS-CoV-2 began to emerge in Wuhan, Hubei, China in December 2019. It is currently spreading globally including Japan. The COVID-19 case in Japan began to appear in middle January 2020 and continued to increase over time. The period from middle January to the end of February is considered to be the initial stage of domestic transmission in Japan. This article described the spread of 935 COVID-19 cases related to Japan by the end of February 2020, including the 15 infected Japanese returned from Wuhan, the 696 infected individuals in the large-scale cruise ship 'Diamond Princess' and the 224 infected individuals in Japan. This paper summarizes the measures to control the spread of SARS-CoV-2 in Japan, such as limiting RT-PCR detection for SARS-CoV-2, reducing the number of patients with mild illness who go to medical institutions unnecessarily, formulating guidelines for SARS-CoV-2 infection consultation, canceling large gatherings and temporarily closing schools. This paper further points out the problems encountered in the prevention and control of the spread of SARS-CoV-2 in Japan, such as the slow detection of RT-PCR, the risk of infection faced by medical staff, the regional differences in the domestic health care service system, the confusion of information disclosure and management. The above introduction as allows us to acquire a better understanding of the new coronavirus pneumonia in Japan and the world and may provide reference for the control the epidemic of COVID-19 in worldwide.