Chicago Tribune from Chicago, Illinois • 166

i U0 ftoatfl Skm Do Salk Shots Really Prevent Polio? Should We Keep Using Salk Inoculations? How Good Are the New Oral Vaccines? Here Are the Facts: If i 4ta niiitBi f-WfrriifcW. tmmm i "-Wei. their children vaccinated. Altho some physicians remained skeptical about the original theories behind the vaccine, about the techniques used in its evaluation, and about its success in combating polio, these objections seldom reached the general public. With the resurgence of paralytic polio in 1958 and 1959, the criticisms increased.

These views were summed up by five experts in a panel discussion on the "Present Status of Polio Vaccines presented before the Illinois State Medical society in Chicago, in May, 1960, and published in the August and September issues of the Illinois Medical Journal. To make parents aware of the controversy about the Salk vaccine and the problems involved in developing an effective oral vaccine against polio, here is a report of that discussion: Dr. Jonas E. Salk injects a volunteer with his vaccine in 1954 field trials. Controversial from the first, the Salk vaccine is still a topic hotly debated.

TlToderator of the panel was Herbert Ratner, M. 1TJ. director of public health in Oak Park, and asso By Joan Beck ciate clinical professor of preventive medicine and public health, Stritch School of Medicine, Chicago. Dr. Ratner noted the upward trend in polio, particularly in the paralytic form, in the United States during 1958 and 1959.

He quoted Dr. Alexander Lang-muir, in charge of polio surveillance for the United States public health service, as saying this resurgence is cause for immediate concern." "In the fall of 1955, Dr. Langmuir had predicted that by 1957 there would be less than 100 cases of paralytic polio in the United States," commented Dr. Ratner. "Four years and 300 million doses df Salk vaccine later, we had in 1959 approximately 6,000 cases of paralytic polio, 1,000 of which were in persons who had received three and more shots of Salk vaccine.

Salk vaccine hasn't lived up to expectations." Dr. Sabin says the number of cases in 1960 was less than in 1959, but that 23 per cent are now occurring in persons who have had three or more doses of Salk vaccine. Dr. Ratner next reviewed some basic facts about polio. Paralytic polio occurs in cycles and was in a natural decline when the Salk vaccine was introduced in 1955, he pointed out.

Prior to the introduction of the Salk vaccine, the National Foundation defined an epidemic -as 20 or more cases of polio per year, per 100,000 population. Now, an epidemic is defined as 35 cases per year per 100,000. This change has resulted in a statistical but not necessarily a real drop in polio epidemics. For every case of known paralytic polio, there are about a thousand subclinical polio infections," so mild they pass unnoticed, Dr. Ratner explained.

These mild cases account for the high degree of natural immunity in adults. You can have a polio infection in the intestines without having paralytic polio or nonparalytic polio with enough symptc ns to be diagnosed. The theory of the Salk vaccine, made with killed polio virus, is that it will produce enough antibodies Chicago Sunday Tribune MAGAZINE declared at the A. M. A.

clinical meeting," the Journal of the American Medical association reported in December, 1960. "The new oral poliomyelitis vaccine developed by Dr. Albert Sabin and approved for future use in this country will not be the complete solution as far as can be predicted now, the public health service experts said." Evaluating the true effectiveness of the Salk vaccine and the new oral vaccines has been difficult for several reasons. Polio is a relatively rare disease in the United States. Because so few persons get it in its paralyzing form, success of an immunizing agent is hard to determine.

The definition of polio also has changed in the last six or seven years. Several diseases which were often diagnosed as polio are now classified as aseptic meningitis or illnesses caused by one of the Coxsackie or Echo viruses. The number of polio cases in 1961 cannot accurately be compared with those in, say 1952, because the criteria for diagnosis have changed. Even the Salk vaccine itself is not a constant, standard product. Since the first field trials of 1954, the vaccine has been changed several times.

The first alterations were aimed at increasing the vaccine's safety by changing the method of killing the polio virus and by adding an extra filtration step. Newer changes are intended to increase the vaccine's effectiveness. The success of the Salk vaccine necessarily varies, depending upon which Salk vaccine is being considered. Ever since the public was first informed about the Salk vaccine in the Francis report of April 12, 1955, the National Foundation has praised its effectiveness and urged parents to have themselves and BEHIND GLOWING reports of the Salk polio vaccine's success and even rosier predictions about the new, live, oral Sabin vaccine rages a storm of medical controversy that seldom reaches the ears of parents. Many serious criticisms have been leveled at the Salk vaccine.

These are now being acknowledged at least indirectly in announcements praising and promoting the new oral vaccines. Yet all is not yet sweetness and accord among developers of the live, oral vaccines, either. At least three different types have been developed and according to their producers proved safe and effective in tests, chiefly in foreign countries, but also in the United States. One of these new oral vaccines, developed by Dr. Albert Sabin with National Foundation research funds, has been OK'd by the United States public health service for manufacture.

But there are problems remaining to be solved in its production and, according to a committee of experts headed by Dr. Roderick Murray of the National Institute of Health, dangers to be considered in its use by the general public (altho it has been given to a reported 77 million Russians and to at least 300,000 Americans. Russian Prof. Mikhail Chumakov, who directed a two year program of inoculation with the Sabin vaccine, says he is convinced polio epidemics have been eliminated in the Soviet Licensing is not expected until this spring. Quantities of the vaccine are not expected to be available for community-wide use until November.

"Both 'live (Sabin) and 'killed' (Salk) polio-virus vaccines will be needed to combat poliomyelitis in the near future. United States public health officials 8.