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International Notes Orthopoxvirus Infections

The World Health Organization (WHO) Committee on Orthopoxvirus Infections met in Geneva, Switzerland, March 24-26, 1986 (1). The following is a summary of some of the major topics discussed and several proposals for action drafted at that meeting.

Smallpox vaccination policy: All member states of WHO report that they have discontinued routine smallpox vaccination and that a certificate of smallpox vaccination from international travelers is no longer required in any country in the world. However, some countries continue to vaccinate military personnel; the Committee recommends that this practice be discontinued.

The original WHO recommendation for discontinuing smallpox vaccination was formulated before the development of techniques using modified (recombinant) strains of vaccinia virus as vectors (carriers) for the expression of antigens to protect against diseases other than smallpox. The WHO recommendation against smallpox vaccination does not apply to the use of vaccinia for immunization against diseases other than smallpox.

Reserve stocks of smallpox vaccine: Because nearly a decade has passed since the last case of endemic smallpox, the Committee felt that it is no longer necessary for WHO to maintain a global reserve of smallpox vaccine.

Investigation of suspected cases: Only 10 rumors of suspected cases of smallpox were reported to WHO in 1985. The Committee concluded that investigation of rumors in the future could be carried out by medical authorities of the member states of WHO.

Retention of variola virus stocks: Only two laboratories (the Centers for Disease Control, in Atlanta, and the Research Institute of Viral Preparations, Moscow, U.S.S.R.), still maintain stocks of variola (smallpox) virus. Neither laboratory plans to resume experiments involving the culturing of variola virus. The variola gene pool has been cloned into nonexpressing sites in bacterial plasmids to allow future study of the variola virus. The Committee's opinion is that it will not be necessary to retain stocks of viable variola virus after the cloning of DNA from variola has been completed, and recommends that remaining stocks be destroyed at that time.

Monkeypox: In 1985, 55 cases of human monkeypox were reported; all cases were from Zaire. WHO has sponsored intensive surveillance activities in a population of about five million people in Zaire. The incidence of human monkeypox is very low, and confidence is growing that the virus cannot sustain itself in human-to-human spread. The Committee recommended that WHO discontinue its direct involvement in monkeypox surveillance at the end of 1986. Reported by International Health Program Office, Div of Viral Diseases, Center for Infectious Diseases, CDC.

Editorial Note

Editorial Note: The last endemic case of smallpox occurred in October 1977 in Somalia. Two cases of smallpox occurred in the United Kingdom in 1978 associated with a smallpox research laboratory. The Committee on Orthopoxvirus Infections observed that in October 1987, 10 years will have elapsed since the last case of endemic smallpox--a more than adequate period of time to provide full assurance that naturally occurring smallpox will not recur.


  1. World Health Organization. Committee on orthopoxvirus infections. Report of the fourth meeting. Weekly Epidemiological Record 1986;61:289-93.

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