Background As countermeasures against the COVID-19 outbreak, sports and entertainment events were canceled (VEC) in Japan for two weeks from 26 February through 13 March. Moreover, most schools were closed (SC). Objective For this study, we estimated the basic reproduction number (R 0 ) and SC and VEC effects. Method After constructing a susceptible–infected–recovered model with three age classes, we used data of symptomatic patients in Japan for 14 January through 24 March. The SC and VEC effects were incorporated into the model through changes in contact patterns and contact frequencies among age classes. Results Results suggest R 0 as 2.56, with 95% CI of [2.51, 2.96]. The respective effects of SC and VEC were estimated as 0.4 (95% CI [0.3, 0.5]) and 0.5 (95% CI [0.3, 0.7]). Conclusion The estimated R 0 is similar to those found from other studies of China and Japan. Significant reduction of contact frequency has been achieved by SC and VEC. Nevertheless, its magnitude was insufficient to contain the outbreak.

Background: To control COVID-19 outbreak in Japan, sports and entertainment events were canceled in Japan for two weeks from 26 February to 13 March. It has been designated as voluntary event cancellation (VEC).Object: This study predicts the effectiveness of VEC enduring and after its implementation.Method: We applied a simple susceptible-infected-recovery model to data of patients with symptoms in Japan during 14 January to VEC introduction and after VEC introduction to 8 March. We adjusted the reporting delay in the latest few days.Results: Results suggest that the basic reproduction number, R 0, before VEC introduced as 2.29 with a 95% confidence interval (CI) was [2.19, 2.37] and the effective reproduction number, R v, after VEC introduced as 1. 99; its 95% CI was [1.

Background In Japan, as a countermeasure against the COVID-19 outbreak, both the national and local governments issued voluntary restrictions against going out from residences at the end of March 2020 in preference to the lockdowns instituted in European and North American countries. The effect of such measures can be studied with mobility data, such as data which is generated by counting the number of requests made to Apple Maps for directions in select countries/regions, sub-regions, and cities. Objective We investigate the associations of mobility data provided by Apple Inc and an estimate an an effective reproduction number R(t). Methods We regressed R(t) on a polynomial function of daily Apple data, estimated using the whole period, and analyzed subperiods delimited by March 10, 2020. Results In the estimation results, R(t) was 1.72 when voluntary restrictions against going out ceased and mobility reverted to a normal level. However, the critical level of reducing R(t) to <1 was obtained at 89.3% of normal mobility. Conclusions We demonstrated that Apple mobility data are useful for short-term prediction of R(t). The results indicate that the number of trips should decrease by 10% until herd immunity is achieved and that higher voluntary restrictions against going out might not be necessary for avoiding a re-emergence of the outbreak.

Background To control the COVID-19 outbreak in Japan, sports and entertainment events were canceled and schools were closed throughout Japan from February 26 through March 19. That policy has been designated as voluntary event cancellation and school closure (VECSC). Object This study assesses VECSC effectiveness based on predicted outcomes. Methods A simple susceptible–infected–recovered model was applied to data of patients with symptoms in Japan during January 14 through March 26. The respective reproduction numbers for periods before VECSC (R0), during VECSC (Re), and after VECSC (Ra) were estimated. Results Results suggest R0 before VECSC as 2.534 [2.449, 2.598], Re during VECSC as 1.077 [0.948, 1.228], and Ra after VECSC as 4.455 [3.615, 5.255]. Discussion and conclusion Results demonstrated that VECSC can reduce COVID-19 infectiousness considerably, but after VECSC, the value of the reproduction number rose to exceed 4.0.

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Background: In Japan, as a countermeasure against the COVID-19 outbreak, voluntary restrictions against going out (VRG) have been applied.Object: We examined mobility information provided by Apple Inc. to a susceptible-infected-recovery model.Method: When applying a polynomial function to daily Apple data with the SIR model, we presumed the function up to a cubic term as in our earlier study.Results: Estimation results demonstrated R 0 as 1.320. The linear, quadratic, and cubic terms of Apple data were, respectively, -33. 7343, 35.4837, and -11.2014. The range of the 95% confidence interval was small, covering almost the entire epidemic curve.

Background: To control COVID-19 outbreak in Japan, sports and entertainment events were canceled in Japan for two weeks from 26 February to 11 March. It has been designated as voluntary event cancellation (VEC).Object: This study predicts the effectiveness of VEC enduring and after its implementation.Method: We applied a simple susceptible-infected-recovery model to data of patients with symptoms in Japan during 14 January to VEC introduction and after VEC introduction to 8 March. We adjusted the reporting delay in the latest few days.Results: Results suggest that the basic reproduction number, R 0, before VEC introduced as 2.50 with a 95% confidence interval (CI) was [2.43, 2.55] and the effective reproduction number, R v, after VEC introduced as 1. 88; its 95% CI was [1.68,2.02].Discussion and Conclusion: Results demonstrated that VEC can reduce COVID-19 infectiousness by 35%, but R 0 remains higher than one.

In Japan, some measles outbreaks were initiated by a tourist from oversea and foreign workers recently. Moreover, rubella outbreak emerged since July 2018 mainly in the South Kanto, and the outbreak is currently ongoing in 2019. It is important to maintain a high measles-rubella combined vaccine (MR) coverage for measles-rubella control. Vaccination coverage for the second dose of MR (MR2) is 90.8% in Tokyo in 2016, which was the third worst among all prefectures in Japan. The purpose of this study was to clarify determinant factors of vaccination coverage for MR2 in Tokyo. Data were obtained for 49 wards and cities in Tokyo in 2016. We regressed vaccination coverage of MR2 on the times of notification by mail, the proportion of households receiving welfare payments, and the proportion of non-Japanese elementary school students. In addition to the simplest specification, five factors were included separately as explanatory variables: the proportion of public health nurses; the ratio of the number of pediatric medical facilities to the number of preschool and elementary school children; the moving-in rate; the proportion of households with a single parent; and the proportion of households with husband and wife both working. Results show that a high proportion of households receiving welfare payments, notification by two or more letters, and moving-in rate or a lower proportion of non-Japanese elementary school students improve coverage. In conclusion, the health authorities can exert efforts to reduce burden of time spent for vaccination and provide sufficient information to improve coverage.