1. Risk Management Office for COVID-19, Department of Health and Medical Care, Okayama Prefectural Government
2. Department of Intractable Diseases, Health Service Bureau, Ministry of Health, Labour and Welfare
3. Bureau of International Health Cooperation, National Center for Global Health and Medicine
4. Okayama Prefecture Mimasaka Public Health Center
5. Okayama Prefecture Maniwa Public Health Center
6. Department of Health and Medical Care, Okayama Prefectura Government
7. Department of Epidemiology, Faculty of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University