Marked temporal decline in human herpesvirus-8 seroprevalence among people living with HIV in Istanbul, Türkiye.

Human herpes virus 8 (HHV-8) drives Kaposi's sarcoma and other lymphoproliferative disorders, especially in PLWH. There are differences in the prevalence of HHV-8 according to countries and geographical regions. Current knowledge on HHV-8 infection in Türkiye relies on sparse and outdated data, leaving a significant gap. To close this knowledge gap, we aimed to generate an up-to-date estimate of HHV-8 seroprevalence in PLWH in Istanbul, Türkiye. In this study, a cross-sectional sero-survey of 368 PLWH whose blood samples were referred from six tertiary hospitals in Istanbul. HHV-8 IgG antibodies were detected with a commercial ELISA. Demographic data and HIV-RNA results accompanied each specimen. Categorical variables were compared with χ² or Fisher's exact tests; continuous variables with independent-samples t-tests (p < 0.05). HHV-8 IgG antibodies were detected in 3 % of PLWH. No seropositive cases occurred in the 0-30-year age group, whereas rates peaked in the 51-60 (5.3 %) age group. Seropositivity was 4.2 % in females and 2.8 % in males (p > 0.05). Among HIV-RNA-positive patients, HHV-8 positivity was 3.4 % versus 2.7 % in HIV-RNA-negative patients (p > 0.05). This multicenter representative study reveals that HHV-8 circulation among PLWH in Istanbul has declined to a low level. The absence of antibodies in younger adults suggests a recent reduction in saliva-mediated transmission, potentially linked to pandemic-driven measures. By providing the first robust sero-epidemiological estimate in over a decade, the study supplies an essential baseline for future public-health planning in Türkiye.