The Pediatric Infectious Disease Society of Thailand (PIDST) was celebrate the 20th anniversary of PIDST on the Annual Meeting of PIDST during May 1-3, 2015 at Royal Cliff Beach Hotel, Pattaya, Thailand and was held one day workshop on "National Immunization Program and Vaccine Coverage in ASEAN countries" on April 30, 2015 in which 80 representativeness from ASEAN countries attended.