Won Suk Choi1,2, Hee Jin Cheong1,3. 1. Division of Infectious Diseases, Department of Internal Medicine, Korea University College of Medicine, Seoul, Korea. 2. Committee of Adult Immunization, The Korean Society of Infectious Diseases, Seoul, Korea. 3. Committee of Adult Immunization, The Korean Society of Infectious Diseases, Seoul, Korea. heejinmd@korea.ac.kr.