Biopharmaceutical Products in the U.S. Market Sample Genenic Monograph 260 . . There is only one major serotype.
Humans are the only natural reservoir of the virus.
Hepatitis A cannot be differentiated from other types of viral hepatitis based on clinical or epidemiologic features alone. Serologic testing to detect IgM antibodies to the capsid proteins of hepatitis A virus is required to confirm a diagnosis of acute hepatitis A infection. In most persons, IgM antibodies become detectable 5-10 days after infection and can persist for up to 6 months after infection. IgG antibodies remain detectable for the person's lifetime after infection and confer lifelong protection against the disease. Synthetic peptides and subunit vaccines containing purified natural or recombinant capsid proteins, theoretically, could provide protection against hepatitis A virus infection.