Hepatitis and hepatitis A vaccine: a glimpse of history.

Human hepatitis has been recognized since the dawn of recorded history, but proof of infectious etiology and delineation of hepatitis A (infectious hepatitis) from hepatitis B (serum hepatitis) were not established until the first half of the present century. Development of the present killed hepatitis A vaccine depended on a series of breakthrough discoveries made during the last 25 years. These were marmoset propagation (1967); definition of virus attributes (1974-1975); development of diagnostic tests and seroepidemiology (1974-1975); and the preparation and proof of efficacy of a prototype killed hepatitis A vaccine (1976). Successful cultivation of hepatitis A virus in cell culture in 1979 quickly led to development of both live and killed hepatitis A vaccines for tests in human beings (1980-1990). The year 1991 marks the initiation of protective efficacy trials of two different killed virus vaccines in human beings. The safety and protective efficacy of the first vaccine (Merck) is reported in this symposium and the findings in tests of a second vaccine (SKB) are awaited. Hepatitis A is clearly a conquerable disease, initially in its elimination as an important disease entity and eventually in its eradication.