Clinical Information

The hepatitis A virus is an RNA containing virus that lacks an envelope. It belongs to the family of picornaviruses. To date, just one human serotype and seven genotypes have been described. The viral capsid consists of three proteins (VP1-VP3) that form an immunodominant structure on the surface of the viral particle that is highly conserved between all genotypes. After vaccination or natural infection, the immune response is directed against this structure. Hepatitis A is the most common form of acute viral hepatitis. It is transmitted by the fecal-oral route. Hepatitis A is typically a self-limiting disease and is often a subclinical disorder, particularly in children.

Symptomatic hepatitis A virus (HAV) infections can be clinically indistinguishable from infection with hepatitis B or C virus therefore serological testing is an important tool for proper diagnosis. An acute or recently acquired HAV infection can be assumed if anti-HAV IgM antibodies are detected. Anti-HAV IgM antibodies can always be detected at the onset of the disease and usually disappear 3 to 4 months later; however, IgM antibodies may be detected in some patients for a longer period. HAV IgM antibodies develop only very rarely after vaccination.