Individual-based epidemiological model of COVID19 using location data

Because human movement spreads infection, and mobility is a good proxy for other social distancing measures, human mobility has been an important factor in the COVID19 epidemic. Therefore, the control of human mobility is one of the countermeasures used to suppress an epidemic.As a notable feature, COVID19 has had multiple waves (subepidemics). Understanding the causes of the start and end of each wave has important implications for a policy evaluation and the timely implementation of countermeasures. Some of the waves have been correlated with the changes in mobility, and some can be attributed to the emergence of new variants. However, the start and end of some of the waves are difficult to explain through known factors.To evaluate the effect of human mobility, we built a stochastic model incorporating individual movements of 500,000 people obtained from anonymized, user-approved location data of smartphones throughout Japan. Instead of using aggregate values of human mobility, our model tracks the movements of individuals and predicts the infection of all persons within the entire country. Although the model only has a single static parameter, it successfully reproduced the occurrence of three waves of the number of confirmed cases within the study period of March 01 to December 31, 2020 in Japan. It was previously difficult to explain the end of the second wave and the start of the third wave in the study period by human mobility alone. Our results suggest the importance of tracking individual movements instead of relaying the aggregate values of human mobility. © 2022 IEEE.

The Impact of Changes in Anthropogenic Activity Caused by COVID-19 Lockdown on Reducing Nitrogen Dioxide Levels in Thailand Using Nighttime Light Intensity

Coronavirus disease 2019 (COVID-19) was first identified in Wuhan, China and has since become a pandemic. Thailand's first lockdown started in the middle of March 2020, restricting anthropogenic activities and inter-provincial traffic. There are few studies on the association between nitrogen dioxide (NO2) levels and human activity, primarily because of the difficulty in identifying the changes in anthropogenic activities at a high geographical resolution. Here, we have highlighted satellite-based nighttime light (NTL) as an indicator of anthropogenic activities and investigated the relationship between NTL and reductions in NO2 levels during Thailand's first lockdown in 2020. We applied geographically weighted regression (GWR) to analyze the regional relationship between NTL and changes in NO2 levels during the first lockdown. Sentinel-5 Precursor satellite observation indicated that the NO2 levels decreased by 10.36% compared with those of the same period in 2019. The level of NTL decreased in most urban and built-up (31.66%) categories. According to GWR results, NTL and NO2 levels represent a positive local correlation around the country's central, western, and northern parts and negative correlations in the peripheral regions. These findings imply that NTL observations can be used to monitor changes in NO2 levels caused by urban anthropogenic activities. © 2023 by the authors.

Information Seeking and COVID-19 Preventive Behaviors: A Comparison Between Immigrants and the Host Population in Japan

Little is known about information seeking and its influence on preventive behaviors among immigrants in Japan, despite their vulnerabilities during the coronavirus disease 2019 (COVID-19) pandemic. This study investigated information seeking about COVID-19, and examined differences with compliance with preventive measures between immigrants and the host population in Japan based on an Internet survey conducted in October 2021. We used chi-squared tests to determine the difference in information seeking and preventive behaviors between the two groups, and Poisson regression with robust standard errors to examine the association between information seeking and compliance with preventive measures. Our results show that, although the overall tendencies of information seeking and the preventive behaviors of immigrants were similar to those of the Japanese, significant differences were identified in some behavior: immigrants were more likely to acquire COVID-19 information from social networking services (SNS) and official websites in Japan, and maintain physical distance and ventilation than Japanese locals. Furthermore, immigrants' sources of information diversified according to their sociodemographic characteristics (e.g., educational level, Japanese language skills, length of residence in Japan, and country or region of origin). Additionally, the effects of information seeking on preventive actions against COVID-19 differed according to the information sources;some information sources (e.g., SNS) had different impacts on preventive behaviors between immigrants and Japanese locals. Obtaining information from traditional media and Japanese official websites increases engagement with all five preventive measures among immigrants and four measures among the Japanese. The study highlights the importance of customized health policies for immigrants according to their behavioral tendencies. © Fuji Technology Press Ltd.

Unwillingness to cooperate with COVID-19 contact tracing in Japan.

OBJECTIVES: Contact tracing for COVID-19 relies heavily on the cooperation of individuals with authorities to provide information of contact persons. However, few studies have clarified willingness to cooperate and motivation to provide information for contact tracing. This study sought to describe willingness to cooperate and motivation to report contact persons for COVID-19 contact tracing among citizens in Japan, and to assess any associated sociodemographic factors. STUDY DESIGN: Cross-sectional study. METHODS: This was an online-based survey using quota sampling. Participants were asked about their willingness to cooperate in reporting contacts for COVID-19 contact tracing if they tested positive. Participants also responded to questions regarding their reasons for cooperating or not cooperating and provided sociodemographic data. Multiple logistic regression analysis was performed to clarify associations between sociodemographic factors and willingness to cooperate. RESULTS: This study included 2844 participants. The proportion of participants who were not willing to cooperate in reporting contacts was 27.6%, with their main reasons being concerns about causing trouble for the other person and being criticised for revealing their names. Willingness to cooperate was lower among men, young adults and those with an educational level less than a university degree. CONCLUSIONS: To improve the effectiveness of contact tracing, educational campaigns, such as reducing the fear and stigma associated with COVID-19, may be important. Furthermore, it is essential to understand that individuals may have contacts whom they do not wish to disclose to others and to be considerate when handling such situations.

Adoption of personal protective measures by ordinary citizens during the COVID-19 outbreak in Japan. (Coronavirus (COVID-19) collection.)

Objectives: To clarify the implementation status of personal protective measures by ordinary citizens in Japan during the coronavirus disease 2019 (COVID-19) outbreak.