1. Use of 13-Valent Pneumococcal Conjugate Vaccine and 23-Valent Pneumococcal Polysaccharide Vaccine Among Adults Aged ≥65 Years: Updated Recommendations of the Advisory Committee on Immunization Practices
2. Committee for discussing Pneumococcal Vaccine Revaccination, National Institute of Infectious Diseases (NIID) Japan. [Guidelines on Pneumococcal Vaccine Revaccination]. 2009. [cited 2020 Dec 7]. Available from: http://www.kansensho.or.jp/uploads/files/guidelines/pneumococcus_vaccine.pdf
3. World Health Organization. Pneumococcal disease [cited 2020 Mar 25]. Available from: https://www.who.int/ith/diseases/pneumococcal/en/
4. Vital, Health and Social Statistics Office, Ministry of Health, Labour and Welfare. [Number of deaths, confirmed numbers, vital Statistics]. 2020. [updated 17 Sept 2020; cited 2020; cited 2020 Sept 2020; cited 2020 17 Dec 17 Sept 2020; cited 2020 17]. Available from: https://www.e-stat.go.jp/stat-search/files?page=1&layout=datalist&toukei=00450011&tstat=000001028897&cycle=7&year=20190&month=0&tclass1=000001053058&tclass2=000001053061&tclass3=000001053065&stat_infid=000031982756&result_back=1&result_page=1&tclass4val=0
5. National Center for Immunization and Respiratory Diseases, Division of Bacterial Diseases, Centers for Disease Control and Prevention (CDC). About pneumococcal disease. [updated 21 Nov, 2019; cited 2019; cited 2020 Nov, 2019; cited 2020 25 Mar 21 Nov, 2019; cited 2020 25]. Available from: https://www.cdc.gov/pneumococcal/about/index.html