Questions and Answers About Smallpox Surveillance & Investigation
How many people would have to get smallpox before it is considered an outbreak?
One confirmed case of smallpox is considered a public health emergency.
How do we expect a smallpox attack to occur, if one happens?
The deliberate release of smallpox as an epidemic disease is now regarded as a possibility. We can’t say with certainty how an attack might occur, but we do know how smallpox is normally transmitted. Transmission most often occurs through person-to-person contact, more rarely through contact with materials contaminated with the smallpox virus, rarely through airborne contagion in enclosed settings. Because an attack could have such serious consequences, every effort is being made to prepare for such a possibility even though it is unlikely to ever occur. These preparedness efforts therefore include use of the best way to prevent smallpox: vaccination.
What would we do if there was an outbreak in Mexico/Canada?
An outbreak of smallpox anywhere in the world would be a global emergency, and that the U.S. would assist any country in control effort, including the provision of vaccine.
During a smallpox emergency, would children under 18 receive the vaccine?
During a smallpox emergency, all contraindications to vaccination would be reconsidered because the risk posed by smallpox disease far outweigh those posed by the vaccine, and persons would be advised by public health authorities on recommendations for vaccination at that time. Children between the ages of 12 months and 18 years would be eligible for vaccination.
Is the decision that there would be no contraindications during a smallpox emergency based on public health data or studies?
As with any public health intervention, the risk of the intervention must be balanced against the risk of the disease. During a smallpox bioterrorism event, the risk of disease would outweigh that posed by the vaccine and thus merit vaccination for many persons who are not recommended for vaccination now. However, the only situation that would lead to no (or nearly no) contraindications to vaccination is a direct, high-risk exposure to smallpox, such as would occur in a household with a person ill with smallpox case. This recommendation is based on extensive experience in the past that suggests that many people with these types of exposures will contract smallpox if not vaccinated.
- Page last reviewed: March 13, 2009
- Page last updated: February 22, 2016
- Content source: CDC Emergency Risk Communication Branch (ERCB), Division of Emergency Operations (DEO), National Center for Emerging and Zoonotic Infectious Diseases (NCEZID)
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