For thousands of years, smallpox epidemics ravaged populations, often killing half of those infected and leaving many of the others horribly scarred. Fortunately, massive immunization campaigns eradicated the disease in the late 20th century. So successful was this effort that the United States stopped vaccinating newborns around 1970. However, the virus still exists in heavily secured medical facilities for research purposes. Therefore, an accidental or malicious release of that viral material in the near future could easily devastate the United States economically in the near term by killing the most productive members of society and disfiguring countless others.

Which of the following, if true, most seriously weakens the argument?