Table 1.

Clinical and Epidemiological Features of Smallpox and Considerations for Certification

Feature	Indications of Smallpox
Incubation period	14–17 d
Syndrome visible	Yes (eruption)
Recognized by public	Yes (eruption)
Asymptomatic carriers	None
Transmission mode	Respiratory
Vector/reservoir	Human
Secondary attack rate among susceptible persons	High (40%–90%)