Recent HIV infections and associated risk factors among newly diagnosed individuals in South Korea (2016–2023)

To develop targeted prevention strategies, identifying the proportion of individuals newly diagnosed with human immunodeficiency virus (HIV) each year, with the infection acquired within 130 days, is essential. We assessed populations at increased risk of HIV infection and identified those with delayed diagnosis by analyzing the proportion of recent infections among newly diagnosed individuals. HIV-antibody avidity assays were used to distinguish recent from longstanding infections among newly diagnosed cases in 2016–2023. Logistic regression analysis was used to assess risk factors among demographic and behavioral data, including age, nationality, region, transmission mode, marital status, HIV-testing purpose, and occupation. We investigated 7,545 individuals, representing 85.0% of the 8,875 newly diagnosed HIV-positive cases in 2016–2023. The average proportion of recent HIV infections (RHIs) throughout the study was 26.1%, being significantly higher among males (26.9%, P = 0.034), individuals aged < 30 years (38.8%, P < 0.001), and Korean nationals (27.3%, P < 0.001). Among testing purposes, blood donation screening yielded the highest proportion of RHIs (45.8%). Male sex, age below 30 years, and Korean nationality were identified as main risk factors for HIV infection. The RHI proportion serves as a key indicator of HIV prevention effectiveness in Korea and can inform development of effective prevention strategies.