Geographical Profiles of COVID-19 Outbreak in Tokyo: An Analysis of the Primary Care Clinic–Based Point-of-Care Antibody Testing

Abstract

Introduction: The primary care clinic plays a major role in triage for coronavirus disease 2019 (COVID-19), where seroprevalence in the setting of primary care clinic remains less clear. As a point-of-care immunodiagnostic test for the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the serosurvey represents an alternative to the polymerase chain reaction (PCR) test to measure the magnitude of COVID-19 outbreak in the communities lacking sufficient diagnostic capability for PCR testing. Methods: We assessed seropositivity for the SARS-CoV-2 IgG between April 21 and May 20, 2020, at 2 primary care clinics in Tokyo, Japan. Results: The overall positive percentage of SARS-CoV-2 IgG was 3.83% (95% confidence interval [CI]: 2.76-5.16) for the entire cohort (n = 1071). The 23 special wards of central Tokyo exhibited a significantly higher prevalence compared with the other areas of Tokyo after classification by residence ( P = .02, 4.68% [3.08-6.79] vs 1.83 [0.68-3.95] in central and suburban Tokyo, respectively). In central Tokyo, the southern area showed the highest seroprevalence compared with the other areas (7.92% [3.48-15.01]), corresponding to the cumulative number of confirmed COVID-19 patients by PCR test reported by the Tokyo Metropolitan Government. Conclusion: The seroprevalence surveyed in this study was too low for herd immunity, suggesting the need for robust disease control and prevention. A regional-level approach, rather than state- or prefectural-level, could be of importance in ascertaining detailed profiles of the COVID-19 outbreak.

Assessing the age specificity of infection fatality rates for COVID-19: systematic review, meta-analysis, and public policy implications

“…Seroprevalence estimates for two locations were excluded because the outbreak was still accelerating during the period when the specimens were being collected and from two other locations for which age-specific seroprevalence was not distinguishable from zero [27,[92][93][94]. Studies of non-representative samples were excluded as follows: 13 studies of blood donors; 5 studies of patients of hospitals, outpatient clinics, and dialysis centers; 4 studies with active recruitment of participants, and 6 narrow sample groups such as elementary schools [19,23,25,26,92,. Supplementary Appendix H lists all excluded studies.…”

“…As shown in fig. 2 , after an initial screening of 1146 studies, we reviewed the full texts of 113 studies, of which 54 studies were excluded due to lack of age-specific data on COVID-19 prevalence or fatalities [ 20 , 24 , 25 , 41 – 91 ]. Seroprevalence estimates for two locations were excluded because the outbreak was still accelerating during the period when the specimens were being collected and from two other locations for which age-specific seroprevalence was not distinguishable from zero [ 27 , 92 – 94 ].…”

“… Hospitals and urgent care clinics. Estimates of seroprevalence among current medical patients are subject to substantial bias, as evident from a pair of studies conducted in Tokyo, Japan: One study found 41 positive cases among 1071 urgent care clinic patients, whereas the other study found only two confirmed positive results in a random sample of nearly 2000 Tokyo residents (seroprevalence estimates of 3.8% vs. 0.1%) [ 24 , 25 ]. Active recruitment .…”

Assessing the Age Specificity of Infection Fatality Rates for COVID-19: Systematic Review, Meta-Analysis, and Public Policy Implications

“…After an initial screening of 1153 studies, we reviewed the full texts of 120 studies, of which 54 studies were excluded due to lack of age-specific data on COVID-19 prevalence or fatalities. [11,15,16,28, Seroprevalence estimates for two locations were excluded because the outbreak was still accelerating during the period when the specimens were being collected and from two other locations for which age-specific seroprevalence was not distinguishable from zero. [ Consequently, our meta-analysis encompasses 34 studies, of which 28 are included in our metaregression and 6 are used for out-of-sample analysis.…”

Infection fatality rate of COVID-19 inferred from seroprevalence data

“…Very low infection fatality rates seem common in Asian countries. 8 , 11 , 29 , 48 , 49 , 51 , 59 , 61 , 67 A younger population in these countries (excluding Japan), previous immunity from exposure to other coronaviruses, genetic differences, hygiene etiquette, lower infectious load and other unknown factors may explain these low rates. The infection fatality rate is low also in low-income countries in both Asia and Africa, 44 , 49 , 66 , 67 perhaps reflecting the young age structure.…”