Hepatitis B and blood safety

Abstract

The safety of blood and blood products is a global issue. Blood transfusion is an important part of modern medicine, but it is also an efficient route of transmission for a number of infectious agents. Although many countries screen all blood donations for a number of infectious agents, a significant proportion of the world's blood supply is either unscreened or poorly screened, with the resultant risk to recipients of transfusion transmitted infections (TTI). Hepatitis B virus (HBV) is of concern because it is transmitted parenterally, many HBV infections are asymptomatic (and infected individuals may thus unwittingly present as blood donors) and the virus is stable in blood and blood products over long periods. The transmission of HBV is minimized by the screening of donors prior to donation, exclusion of high-risk donors, followed by the in-vitro screening of donations for HBsAg (+anti-HBc in some countries) prior to transfusion. However, even in countries with good quality, active screening programmes, there is still a small residual risk of transmission of HBV from undetected donors with early acute infection, resolving infection, silent infection or infection with atypical virus serology. Unfortunately, as with so many infectious agents, the prevalence of HBV is most often higher in those countries with poorly developed healthcare systems and limited resources. In these countries, the safety of the blood supply is compromised frequently either because of lack of resources with which to purchase screening assays, or because of acute blood shortages and insufficient time to screen blood prior to transfusion. In such situations it is important to encourage and actively support the introduction of appropriate screening programmes which can be based upon simple assay formats such as agglutination rather than the favoured but more complex enzyme immunoassays which are more expensive, require specific equipment and support, and take longer to perform. Such approaches will help reduce greatly the transfusion transmission of HBV.