In May 1980, WHO declared the global eradication of smallpox. Currently, there is no evidence of smallpox transmission anywhere in the world. The last reported case of endemic smallpox occurred in Somalia in October 1977, and the last reported case of laboratory-acquired smallpox occurred in the United Kingdom in 1978. WHO amended the International Health Regulations on January 1, 1982, deleting smallpox from the diseases subject to the regulations. Today, concerns about the reemergence of smallpox involve its potential use as a biological weapon (1).

Smallpox vaccination should not be given for international travel. The currently licensed smallpox vaccine is a live-virus vaccine containing vaccinia virus, an orthopoxvirus related to smallpox virus that can provide cross-protection. Smallpox vaccination of civilians is recommended for laboratory workers directly involved with smallpox or closely related orthopoxviruses (e.g., monkeypox, vaccinia, and others) and for public health, medical, and other designated response personnel who may be involved as first responders to an intentional release of smallpox virus (2). In addition, U.S. military personnel may be required to have smallpox vaccination as a part of military force protection policies. Health-care workers whose contact with vaccinia virus is limited to contaminated materials (e.g., dressings) are at a lower risk of inadvertent infection than laboratory workers, but may be considered for vaccination.

In response to a confirmed smallpox outbreak within the United States or internationally, rapid voluntary vaccination may be initiated to

1. supplement priority surveillance and containment control strategies in areas with smallpox cases,
2. reduce the population at risk for additional intentional releases of smallpox virus if the probability of such occurrences is considered substantial, or
3. address heightened public or political concerns regarding access to voluntary vaccination (3-6).

Misuse of Smallpox Vaccine

Smallpox vaccine should never be used for medical reasons other than for the prevention of smallpox or a related orthopoxvirus infection. There is no evidence that smallpox vaccination has therapeutic value in the treatment of recurrent herpes simplex infection, warts, or any other disease.

References

1. Henderson D, Inglesby T, Bartlett J, Ascher MS, Eitzen E, Jahrling PB. Consensus statement: smallpox as a biological weapon: medical and public health management. JAMA. 1999;281:2127-37.
2. CDC. Recommendations for using smallpox vaccine in a pre-event vaccination program: supplemental recommendations of the Advisory Committee on Immunization Practices (ACIP) and the Healthcare Infection Control Practices Advisory Committee (HICPAC). MMWR Morb Mortal Wkly Rep. 2003;52(RR-07):1-16.
3. Henderson DA. Smallpox: clinical and epidemiological features. Emerg Infect Dis. 1999;5:537-9.
4. CDC. Smallpox vaccination and adverse reactions; guidance for clinicians. MMWR Morb Mortal Wkly Rep. 2003;52(RR04):1-28.
5. CDC. Cardiac adverse events following smallpox vaccination — United States, 2003. MMWR Morb Mortal Wkly Rep. 2003;52(12):248-250.
6. CDC. Update: Cardiac and Other Adverse Events Following Civilian Smallpox Vaccination —- United States, 2003. MMWR Morb Mortal Wkly Rep. 2003;52(27):639-642.