Background and objectives: Human B19 parvovirus (B19), identified in 1975,
was only recognised as the causative agent of fifth disease in 1983. The incidence
of viraemia is low, around 1 in 1,000, but is sufficient to ensure that most plasma
pools for fractionation contain some virus. While infection usually occurs in
childhood and is benign, chronic 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
transmission of B19 infection by pooled plasma products. Results: Recent
data on the pathophysiology and assay of this virus are summarised along with
possible approaches to donor screening, product screening, and virus removal.
Only five cases of symptomatic infection have been reported in persons with
haemophilia, but no technology for vims removal is established, and infection
may be of concern in pregnant women, and in patients with enhanced red cell
turnover or who are immunosuppressed, including those infected with human
immunodeficiency vims, but only rarely in immunocompetent patients. Conclusions:
For the future, well-validated assays relevant to vims infectivity are required
if blood donations, plasma pools, or plasma products are to be screened,
and an in-process vims inactivation step for B19 would be highly desirable. In the
interim, non-plasma or recombinant products or a selective transfusion policy
might be used in patient groups in which B19 infection 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 excess B19 infectivity arising from transfused products.