OA2-AM24-ST-06 - HHV-8 Seroprevalence Among Blood Donors in Uganda

Human herpesvirus-8 (HHV-8), also called Kaposi’s sarcoma-associated herpesvirus, is a lymphotropic virus understood to be the oncogenic driver of Kaposi’s Sarcoma, primary effusion lymphoma and Castleman disease. It poses significant morbidity and mortality to vulnerable populations with comorbidities and/or weakened immune systems. Previous epidemiological studies have shown HHV-8 to have a unique geographical distribution with high prevalence in areas of sub-Saharan Africa and moderate levels around the Mediterranean. Large scale serosurveillance studies to characterize the burden of HHV-8 among blood donors in endemic regions are lacking.  A better understanding of infection dynamics within the blood donor pool remains a critical need.

Study

Design/Methods: Blood donors from Kampala, Uganda were evaluated between October 2019 and December 2022 for IgG antibodies using a bead-based multiplex assay optimized using five KSHV antigens (K8.1, K10.5, ORF73, ORF36, and ORF25). HHV-8 seropositivity was defined as a positive result to any of the five antigens. Trends in seroprevalence were evaluated by quarter. Statistically significant associations between HHV-8 seropositivity and blood donor demographics (age, sex), blood type (ABO group, Rh factor), and transfusion transmitted infection (TTI) status (HIV, HBV, HCV, and syphilis) were assessed by chi-square tests. 

Results/Findings: A total of 4833 blood donor samples were evaluated. Overall, 3332 (68.9%) donors were HHV-8 seropositive. Quarterly HHV-8 seropositivity ranged from 61.6% to 76.7%; no significant trends over time were seen. Differences in seropositivity were observed by sex, with male donors having a higher seropositivity (71.7%, n=3547) than female donors (61.2%, n=1284; p< 0.001). Seropositivity also varied by age, with the highest levels seen among those aged 25-29 years (73.2%, n=975) and the lowest levels seen among those aged 16-19 years (57.1%, n=378) and ≥40 years (65.5%, n=461; p< 0.001). Seropositivity was notably higher among donors positive for syphilis compared to those who were negative (82.0% [n=82] vs. 68.6% [n=3245], p< 0.006). The four other TTIs evaluated were also enriched but did not rise to the level of statistical significance. No statistically significant differences in HHV-8 seropositivity were observed among blood donors by ABO group, Rh factor, or HIV, HBV, or HCV serostatus.

Conclusions: Among the blood donor population of Kampala, Uganda, HHV-8 seroprevalence is high, and it varies by risk factors including sex, age, and syphilis serostatus.  Understanding HHV-8 transfusion-transmission dynamics and potential mitigation strategies is critical.