Abstract

Although the virus has not yet been isolated, all the available evidence suggests that infectious hepatitis is a viral illness. Failure to isolate the virus or viruses responsible means that specific antibodies to the virus antigen cannot be produced in the laboratory, neither can the virus be modified artificially and used to evoke active immunity. After an attack of infectious hepatitis an individual is usually immune from further attacks; the antibodies responsible for the immunity are contained in IgG fractions of the gamma globulin.