than half of the introductions of smallpox disease were by citizens of a country when they returned home after being abroad. Because the United States has a high number of international travelers, both citizens and non-citizens, the prospects for importing poliovirus from other locales would seem to be real.

A primary difference between the smallpox and polio situations is the ability to detect cases early and to contain outbreaks. With smallpox, it was relatively easy to detect infected individuals, isolate them, vaccinate those in the surrounding area or those who had been in contact with the infected individual, and successfully curtail an outbreak. Because of the common subclinical infections mentioned earlier, polio is a much different situation. If a paralytic case is detected, there could be many subclinical cases, and historically it has sometimes been difficult to contain outbreaks even with extensive vaccination in an affected area.

There are and were safety issues with respect to both vaccines. Smallpox vaccine was associated with 6 to 12 deaths each year, either in recipients or in contacts, most often in those with immunodeficiencies. In addition, post-vaccination encephalitis occurred at a rate of about 1 per 500,000 vaccinees.

“Significantly, the cause of human cases of polio in the U.S. in the past two decades has been attributed solely to the oral polio vaccine. . . . The current vaccine strategy evokes too many serious questions to maintain in operation, and I suggest that a redirection and reformation of thinking and policy are in order. I also respectfully suggest that the scientific evidence is compelling that the no vaccine option is the only one which will result in no cases of vaccine-associated polio and no damage to the immune and nervous systems of vaccine recipients and their contacts.”

From a presentation by Stephen Marini in advocacy of a no vaccine option, CDC-sponsored polio vaccine workshop, June 8, 1995.


The value of a model is to provide a framework for policy decisions, to clarify what is known and what is unknown, and to determine key factors in decisionmaking. The modeling approach presented is similar to that of


The material in this section is adapted from presentations by Robert Kohberger and Roland Sutter and comments by other workshop speakers or participants.

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