Gamma globulin prophylaxis.

THE importance of infectious hepatitis as a world-wide problem has been highlighted in detail during the presentations made at this symposium. It is clear that as of today (May I 8, I968) there is no published report confirming the isolation of infectious hepatitis virus in a tissue-culture system or animal host. Experience with poliomyelitis, measles, and rubella has revealed that the time interval between isolation of the virus and subsequent vaccine development and licensure has ranged between seven and nine years. Poliomyelitis vaccine was first licensed for use in I 956; the virus was isolated in I 949. Measles virus was identified in tissue culture in I954; the vaccine was licensed in i963, nine years later. Although rubella virus was isolated in I962, it is unlikely that a vaccine will be licensed before i969. Consequently, it seems logical to predict that a vaccine for the prevention of infectious hepatitis will not be developed and licensed before I975.