328 



sion leader.^'' He outlined the agenda of items to be discussed and 

 cautioned the panel and the committee that "there may well be dif- 

 ferences of opinion expressed. * * * and that * * * the popular be- 

 lief * * * that scientists should not disagree * * * is subject to some 

 modification." ^'^ 



The first discussant, Dr. Albert Sabin, described the incidence of 

 polio within the country and detailed epidemiological variations due 

 to type of virus, age, and types of infection and presence of natural 

 immunity.*^^ 



Dr. Joseph Smadel, virologist with the Army's Walter Eeed Medi- 

 cal Center, gave a detailed comparison of the advantages and dis- 

 advantages of inactivated (Salk) vaccine and attenuated (Sabin) 

 vaccine. (Although Congress did not directly treat this question, it 

 was salient for the scientists debating the continuance of the Salk 

 vaccine program.) Advantages of the live attenuated virus included 

 the small amount of vaccine required for antibody production and ease 

 of manufacture. A disadvantage was the difficulty in finding a good 

 mild strain that would be l>oth potent and safe. The advantage of the 

 killed virus was that any strain could be used as long as properly 

 killed. Its disadvantages were that several large injections of vaccine 

 were required for effectiveness; immunity was probably only tem- 

 porary; and achievement of the proper degree of inactivation was 

 difficult without harming the potency of the virus. Moreover, the in- 

 activated vinis vaccine contained animal tissue, used in culturing the 

 vaccine, so that there was a possibility that the inoculated person might 

 contract hepatitis or other infection.''^ 



The discussion then moved to an assessment of both types of vaccine. 

 Dr. Francis asserted that the Salk process was sophisticated enough 

 to remove all hazardous animal impurities which might cause 

 infection.'^" 



Dr. Stanley stated that it would be much too expensive for the com- 

 mercial manufacturer to eliminate all of the potentially hazardous 

 animal protein. Salk asserted that all studies done on humans inocu- 

 lated with the vaccine, which contained kidney tissue, showed that the 

 hazard of infection from animal impurities was nil.'^^ However, Dr. 

 Smadel concluded that : 



When one considers all of these theoretical advantages and disadvantages, most 

 virologists usually conclude that a good live attenuated virus is preferable to 

 a dead one * * *.''" 



"^ other panelists were : Dr. Daniel Bergsma, commissioner of health, New Jersey, and 

 vice president, Association of State & Territorial Health Officers ; Dr. John F. Enders, 

 Children's Hospital, Boston ; Dr. Thomas Francis, Jr., School of Public Health, University 

 of Michigan ; Dr. Horace L. Hodes, pediatrician in chief. Mount Sinai Hospital, New York, 

 and member. Committee on the Control of Infectious Diseases, American Academy of Pedi- 

 atrics ; Dr. Frank L. Horsfall. Jr., Rockefeller Institute for Medical Research, New York ; 

 Dr. Colin MacLeod, Bellevue Medical Center, New York ; Dr. Manfred M. Mayer, School of 

 Hygiene and Public Health, Johns Hopkins University, Baltimore ; Dr. Julian P. Price, 

 member, board of trustees, American Medical Association ; Dr. Thomas M. Rivers, Rocke- 

 feller Institute for Medical Research, New York ; Dr. Albert B. Sabin, Children's Hospital 

 Research Foundation, Cincinnati : Dr. Jonas E. Salk, Virus Research Laboratory, University 

 of Pittsburgh, Pittsburgh; Dr. James A. Shannon, Associate Director, National Institutes 

 of Health ; Dr. Joseph E. Smadel. Army Medical Services. Graduate School, Walter Reed 

 Army Medical Center ; and Dr. Wendell M. Stanley, Biochemistry and Virus Laboratory, 

 University of California, Berkeley. 



<" House. Committee on Interstate and Foreign Commerce. Poliomyelitis vaccine, hearings, 

 pt. 2. op. cit., p. 132. 



esibid., np. 1.34-136. 



89 Ibid., pp. 139-141. 



'"Ibid., p. 141. 



71 Ibid., pp. 145, 147. 



" Ibid., p. 141, 



