2025 Volume 75 Issue 1 Pages 33-39
Background & Aims: Although COVID-19 spread in non-Japanese communities in Japan, epidemic differences between those and Japanese communities are unclear. Factual epidemiological evaluation is needed to improve the existing infection control measures in the whole community.
Methods: This study, conducted among residents of Gunma Prefecture from open data of March 2020 to December 2021, compared COVID reproduction numbers and cumulative infection positive rates in 10 regions between Japanese and non-Japanese residents. Positive cases were also classified into three age groups (－19, 20-59, and 60＋years old), and their proportions among total cases were compared between two groups.
Results: Effective reproduction numbers in the total study population, non-Japanese, and Japanese were 1.26, 1.32, and 1.25, respectively, being slightly higher in non-Japanese. Cumulative positive rates in non-Japanese and Japanese were 6.14% and 0.69%. The positive rates in non-Japanese were significantly higher in all 10 regions. Positive rates were highest in age group 20-59 years old, comprising 80.4% and 62.5% of non-Japanese and Japanese infections, respectively.
Conclusions: Because many non-Japanese in Japan are workers, COVID-19 may more readily spread among them due to high activity. Infection control measures should be expanded among people of working age regardless of nationality.
