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

Determining the annual proportion of individuals newly diagnosed with human immunodeficiency virus (HIV) infection acquired within the preceding 130 days is essential to inform targeted prevention strategies. 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 performed to distinguish recent from longstanding infections among newly diagnosed cases during 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. The average proportion of recent HIV infections (RHIs) was 26.1%, which was 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 < 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.