HUMAN PARVOVIRUS B19 AND BLOOD PRODUCTS

Background and objectives: Human B19 parvovirus (B19), identified in 1 975, was only recognised as the causative agent of fifth disease in 19 83. The incidence of viraemia is low around 1 in 1,000, but is suffici ent to ensure that most plasma pools for fractionation contain some vi rus. While infection usually occurs in childhood and is benign, chroni c infection sometimes occurs and may be of concern in certain patient groups. Materials and methods: This review is based on a meeting held in March 1995, and addresses recent concerns regarding the potential t ransmission of B19 infection by pooled plasma products. Results: Recen t data on the pathophysiology and assay of this virus are summarised a long with possible approaches to donor screening, product screening, a nd virus removal. Only five cases of symptomatic infection have been r eported in persons with haemophilia, but no technology for virus remov al is established, and infection may be of concern in pregnant women, and in patients with enhanced red cell turnover or who are immunosuppr essed, including those infected with human immunodeficiency virus, but only rarely in immunocompetent patients. Conclusions: For the future, well-validated assays relevant to virus infectivity are required if b lood donations, plasma pools, or plasma products are to be screened, a nd an in-process virus inactivation step for B19 would be highly desir able. In the interim, non-plasma or recombinant products or a selectiv e transfusion policy might be used in patient groups in which B19 infe ction is of particular concern. Further clinical data on the prognosis and impact of B19 infection are needed to justify both such policies and the future adoption of new technologies designed to reduce any exc ess B19 infectivity arising from transfused products.