ABSTRACT
Despite the eradication of smallpox, variola virus (VARV) remains a public health concern, because of the possibility that clandestine stocks of VARV may be in the hands of bioterrorists [1]. The impact of a VARV attack in the human population now would be even more catastrophic than it was during the last century: vaccination programs were abandoned worldwide around 1976, the prevalence of immunosuppressed populations has grown, and mobility, including intercontinental air travel, has accelerated the pace of viral spread worldwide. It is for these reasons that considerable investment is being made in the development of improved medical countermeasures (MCM) against smallpox, including new vaccines and antiviral drugs [2,3].
