Prevalence of sexually transmitted infections among persons aged 15–24 in the Republic of Korea: A retrospective population-based descriptive study

PURPOSE: Despite rising sexually transmitted infection (STI) incidence globally, evidence on the burden among adolescents remains limited. This study examined trends in the prevalence and medical costs of STIs among Korean youth aged 15-24 from 2010 to 2023, with a focus on age- and gender-specific disparities. MATERIALS AND METHODS: Using national health insurance claims data from the HIRA (Health Insurance Review & Assessment Service), we identified STI cases by ICD-10 (10th revision of the International Classification of Diseases) codes and calculated annual age-standardized and age-specific prevalence rates based on census data. Sex-stratified analyses were performed, and medical expenditures were estimated and converted to US dollars. RESULTS: Over 2010-2023, STI prevalence among Korean youth rose by 22.9%, peaking in 2019. Rates were consistently higher in the 20-24 group than in the 15-19 group, with human immunodeficiency virus (HIV), genital warts, and mycoplasma showing four- to eight-fold differences. Chlamydia (21.8%) and gonorrhea (18.5%) accounted for the largest share of youth cases. While HIV and nongonococcal urethritis were predominantly male, mycoplasma, chlamydia, and genital herpes were more common in females. Total medical costs reached US$121.9 million, with 77.5% incurred by males, largely driven by nongonococcal urethritis. CONCLUSIONS: STI prevalence among Korean youth has risen steadily despite a shrinking youth population, with substantial gender and age disparities in both disease patterns and medical costs. These findings highlight the urgent need for comprehensive, youth-centered sexual health education and improved access to confidential sexual and reproductive health services in Korea.