Human herpesvirus 8 infection and transfusion history in children with sickle-cell disease in Uganda

Background: Although human herpesvirus 8 (HHV-8), the etiologic agent for Kaposi's sarcoma, can be detected in peripheral blood, blood-borne transmission of this virus has not been demonstrated. We studied the association between HHV-8 seropositivity and transfusion history among children with sickle-cell disease in Uganda, where HHV-8 infection is common in blood donors. Methods: We studied 600 children (aged 0-16 years) with sickle-cell disease at Mulago Hospital, Kampala, from November 2001 through April 2002. By design, about half had previously been transfused. HHV-8 serostatus was determined using enzyme-linked immunosorbent assays for antibodies against HHV-8 proteins K8.1 and orf73. We used logistic regression to test for an association between HHV-8 serostatus and transfusion history and a Markov model to estimate the transmission risk per transfusion and the cumulative risk from community (i.e., nontransfusion) sources. Statistical tests were two-sided. Results: HHV-8 antibodies were detected in 117 of 561 (21%) children with unambiguous K8.1 results. HHV-8 seroprevalence among the never-transfused children increased with age from 7% in children aged 0-2 years to 32% in those aged 13-16 years (P-trend < .001). HHV-8 seropositivity was more frequent in transfused than never-transfused children (24% versus 17%, odds ratio = 1.48, 95% confidence interval [CI] = 0.97 to 2.26; P = .07). Seropositivity increased with number of reported transfusions, with age-adjusted odds ratios of 0.97 (95% CI = 0.54 to 1.75), 1.13 (95% CI = 0.59 to 2.17),1.76 (95% CI = 0.81 to 3.83), and 2.17 (95% CI = 1.18 to 3.99) for children with one, two, three, or four or more transfusions, respectively (P-trend = .007). Overall, the estimated HHV-8 transmission risk was 2.6% per transfusion (95% CI = 1.9% to 3.3%), whereas the annual risk of infection unrelated to transfusion was 2.7% (95% CI = 1.7% to 3.7%). Conclusion: Our study suggests that blood transfusion is associated with a small risk of HHV-8 transmission. In Uganda, this risk is approximately equivalent to the 1-year cumulative risk of infection from community sources.