Hepatitis viruses and the safety of blood donations

Since the beginning of blood transfusions concomitant transmission of viral hepatitis has been a frequent and serious side-effect. A first measure to reduce the frequency of transmission was the screening of blood donors for elevated levels of liver enzymes in the blood, which was introduced in Germ any in the 1960s, but not in most other countries. After the discovery of h epatitis B virus (HBV), donors in all countries have been screened since th e 1970s for its surface antigen (HBsAg). When it was realized that there wa s at least one other type of virus that was even more frequently transmitte d, screening for liver enzymes and HBV antibodies (anti-HBc) was introduced as a surrogate marker in most, but not all, countries in the 1980s. Furthe rmore, donors at risk for parenterally transmitted viruses were excluded. T he discovery of the hepatitis C virus (HCV) genome and the development of s ensitive anti-HCV assays has meant that reliable detection of persistently infected HCV carriers has been possible since 1991, Recently infected donor s, however, are infectious for several weeks or months before anti-HCV is d etectable, Therefore, starting in April 1999 all donations in Germany have to be tested, by nucleic acid amplification tests, for the presence of HCV RNA, although preliminary experience shows that such recent HCV infections are very rare. Newly detected viruses, named GBV-C or HGV and TTV, have bee n detected in patients with non-A-E post-transfusion hepatitis, but their a ssociation with the disease seems to be coincidental. These viruses cause p ersistent viraemia and are quite prevalent world-wide, but do not cause any known disease, At present, transfusion-transmitted hepatitis has been virt ually eliminated, and any improvement in safety will be very small and will require huge costs.