title: Quantifying the source of infection for HIV-infected hemophiliacs in the U.K. from 1979 to 1984.
abstract: There is considerable literature on the risk of HIV infection for individuals suffering from hemophilia A in the United Kingdom (U.K.) during the period 1979-1984 when the sources of Factor VIII clotting factor were contaminated with HIV. Toward the end of this period, several investigators reported HIV prevalence among hemophiliacs, often classified by the severity of disease and, to some extent, the source of the clotting factor with which individuals were infused. In the U.K., hemophilia A patients typically received clotting factor from the local National Health Service (NHS) supplies or from commercial product usually imported from the United States. Litigation on behalf of U.K. hemophiliacs, their survivors, and estates remains unresolved, cases in which it becomes important to quantify the fraction of U.K. hemophiliac HIV infections attributable to imported blood product. For HIV-infected individuals who received Factor VIII from one source exclusively, the source of infection is clear, assuming no other risk factors. For patients who used both types of clotting factor, the source of infection is uncertain. For the U.K. as a whole, we produce quantitative estimates of the conditional probability of infection due to a specific source, based on HIV prevalence in groups exclusively exposed to a specific source and the percentage of clotting factor that was imported. With plausible estimates of these input parameters, an estimate of the conditional probability of infection due to imported product is 0.93 (95 per cent CI: 0.90-0.96). This estimate is relatively insensitive to changes in input parameters, but may vary over subgroups of hemophiliacs.
authors.affiliation: Division of Biostatistics and Department of Statistics, University of California, Berkeley, CA 94720, USA. jewell@berkeley.edu
authors.forename: Nicholas P
authors.initials: NP
authors.lastname: Jewell
mesh_terms: D001699:Biometry; D003029:Coagulants / Q000009:adverse effects / Q000266:history; D004340:Drug Contamination; D005169:Factor VIII / Q000009:adverse effects / Q000266:history; D015658:HIV Infections / Q000150:complications / Q000453:epidemiology / Q000266:history* / Q000635:transmission; D006467:Hemophilia A / Q000150:complications / Q000188:drug therapy / Q000266:history*; D049673:History, 20th Century; D006801:Humans; D008297:Male; D011336:Probability; D012680:Sensitivity and Specificity; D006113:United Kingdom / Q000453:epidemiology
chemical_list: D003029:Coagulants; D005169:Factor VIII