Occurrence of hepatitis A virus genotype III in Germany requires the adaptation of commercially available diagnostic test systems

BACKGROUND: A blood donation, obtained in 2003 in Germany during the preseroconversion diagnostic window period of a hepatitis A virus (HAV) infection, tested HAV‐negative by commercially available HAV reverse transcription–polymerase chain reaction (RT‐PCR) detection assays. STUDY DESIGN AND METHODS: The virus responsible for this infection was identified as HAV genotype IIIA by characterization of the nearly complete genome sequence. RESULTS: Thereby, this HAV variant, which was named strain HMH, was detected in Germany for the first time. Because the commercially available HAV RNA detection systems failed to detect this genotype, a real‐time RT‐PCR kit was developed that allows quantification and detection of all HAV genotypes. The first nearly full‐length nucleotide sequence so far available for HAV genotype IIIA is also provided. CONCLUSION: This case demonstrates that owing to the genetic variability of HAV, constant monitoring and adaptation of the diagnostic nucleic acid assays are required to guarantee the safety of blood and blood products.