Recent HIV Infections in Italy: Data from the HIV National Surveillance System, 2012-2023

The identification of recent HIV infections among newly diagnosed HIV cases is relevant to both implementing targeted prevention measures and estimating HIV incidence. We analyzed data on new HIV diagnoses in Italy from 2012 to 2023. We selected cases that were tested by at least one of three criteria (test for HIV recency, data on HIV seroconversion, clinical signs of acute HIV infection) to assess the rate of recent (<1 year) HIV infections. We analyzed these cases by gender, age group, nationality, and mode of transmission, and revaluated cases that were initially scored as a late diagnosis but then classified as a recent infection. Out of 36,289 new HIV diagnoses, 17,558 (48.8%) were tested for recent infection by at least one criterion and 3772 (21.5%) were classified as recent. At multivariate analysis, the probability of being recently infected was significantly higher among males, people aged 15-44 years, Italians, individuals diagnosed in Northern and Central Italy, heterosexual males, MSM, and people with a CD4 count ≥ 350 cells/uL at diagnosis. Of 8658 cases initially classified as late diagnoses, 979 (11.3%) were reclassified as recent by the aforementioned criteria. Monitoring recent infections among new HIV diagnoses is beneficial to individuals-because it motivates recently infected people to comply with antiretroviral treatment (which is more effective if started early) and to collaborate to partner notification, and to public health, as it provides evidence of epidemiological changes and stresses the need for targeted prevention in well-defined populations at risk.