Smallpox is contagious day prior to the onset of rash In contrast to chickenpox, the rash of smallpox starts on the face and extremities and spreads centrally The smallpox rash develops synchronously such that lesions are all in the same stage Strict airborne, droplet, and contact precautions should be instituted immediately for smallpox victims and should continue until all scabs have separated Smallpox is associated with a high mortality and there is no specific therapy available Background The global eradication of smallpox represents one of the great success stories of public health, with the last endemic case occurring in Somalia in 1977 Since then, research stockpiles of variola virus have been consolidated into two World Health Organization (WHO)–approved stores at the CDC in Atlanta and at a Russian institute in Koltsovo This achievement would seem to make terrorist use of this virus impossible; however, several factors give cause for concern First is the fear that other stockpiles already exist in the hands of belligerent nations unbeknownst to WHO Astonishingly, in 2014, vials containing the smallpox virus were discovered in a storage room of an FDA laboratory in Bethesda, Maryland Second, the entire viral genomic sequence is known and published; therefore, it is likely only a matter of time before technology permits reconstruction of the virus (the related horsepox virus has already been synthesized de novo) Finally, although the virulence factors of variola virus are poorly understood, it may be possible for someone to manipulate related orthopoxviruses such as monkeypox to enhance their virulence in humans and create a disease similar to smallpox In light of these considerations, the CDC in 2003 recommended a strategy of reintroducing vaccination in the United States after a nearly 30-year hiatus, with the initial goal of vaccinating up to 10,000,000 front-line EMS and healthcare providers This program has subsequently proven controversial and has been suspended; probably fewer than 50,000 civilians were vaccinated The U.S military, however, has vaccinated several hundred thousand service members and serious adverse events have been rare Several factors might make smallpox an attractive weapon to potential belligerents First, the duration of immunity after vaccination is a matter of controversy, with some studies suggesting a duration of only to years, while other studies suggest the possibility of lifelong immunity Second, following