[Controlled viral risks].
The prevalence of virological markers in blood donors has been continuously decreasing since the implementation, as soon as they were available, of serological screening methods. In 1998, the prevalences (per 10,000 donations) were 0.17 for antibody to HIV, 0.08 for antibody to HTLV, 2.23 for HBs Ag and 2.52 for antibody to HCV. The values are of course higher in new donors when compared to regular donors: approximately five-fold for HIV, 50-fold for HCV and 300-fold for HBs Ag. The remaining major questions concern the residual risk due to infectious donations which could escape the preventive measures. It seems evident that the major risk is imputable mainly to donations collected during the window period. During the 1996-1998 period, the residual risk for HIV was one out of 1,350,000 donations, 0 for HTLV, one out of 375,000 for HCV, and one out of 220,000 for HBV. A few cases of 'immuno-silent' patients have been reported. They remain exceptional. The first data collected after implementation of Nucleic Acid Technology (NAT) confirm the very low residual risk. The molecular epidemiology of the concerned viruses applied to the evaluation of screening assays highlighted the impact of the genetic diversity on the efficiency of these assays. This is particularly evident for HIV and HBV. The recent introduction of leucodepletion probably brought an important contribution in diminishing the risk of transmission of leucotropic viruses such as cytomegalovirus, Epstein-Barr viruses, human herpesviruses 6 and 7, and HTLV. If the purification process of plasma derived medicinal products including inactivation procedures permits confidence in the elimination of infectivity due to enveloped viruses, the detection of nucleic acid sequences derived from naked viruses in plasma pools may greatly contribute to their safety.
Barin
F
F
Unité de virologie transfusionnelle, Institut national de la transfusion sanguine, Paris, France.
D000914:Antibodies, Viral / Q000097:blood*; D000956:Antigens, Viral / Q000097:blood; D015415:Biomarkers / Q000097:blood; D016913:Blood Component Transfusion; D001782:Blood Donors; D001803:Blood Transfusion / Q000592:standards; D004279:DNA, Viral / Q000097:blood; D006800:Deltaretrovirus Infections / Q000097:blood / Q000175:diagnosis / Q000517:prevention & control / Q000635:transmission; D015658:HIV Infections / Q000097:blood / Q000175:diagnosis / Q000517:prevention & control / Q000635:transmission; D006525:Hepatitis, Viral, Human / Q000097:blood / Q000175:diagnosis / Q000517:prevention & control / Q000635:transmission; D006801:Humans; D007962:Leukocytes / Q000821:virology; D008403:Mass Screening; D015995:Prevalence; D012367:RNA, Viral / Q000097:blood; D012306:Risk; D016036:Seroepidemiologic Studies; D065227:Transfusion Reaction; D014766:Viremia / Q000175:diagnosis*; D014777:Virus Diseases / Q000097:blood / Q000175:diagnosis / Q000453:epidemiology / Q000517:prevention & control* / Q000635:transmission
D000914:Antibodies, Viral; D000956:Antigens, Viral; D015415:Biomarkers; D004279:DNA, Viral; D012367:RNA, Viral