Duration of viremia in human hepatitis A viral infection as determined by polymerase chain reaction.

Viremia in hepatitis A viral (HAV) infection is said to be limited to pre-symptomatic period. However, it is not clear how long viremia lasts in human infection due to the lack of a simple and sensitive detection system. In an attempt to find HAV genome in patients' sera, we used the RT-PCR method by setting a pair of primers in the 5' non-coding region. While in most cases HAV-RNA was detected only before alanine aminotransferase (ALT) reached peak levels with this sensitive system, the viral genome was observed in some patients' sera even after ALT reached peak levels. Some patients also had HAV viremia after seroconversion to HAV antibody. These results show that viremia in HAV infection lasts longer than has been previously thought, and give a warning of possible secondary blood-borne infection.