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Vaccinia Outbreak -- Nevada

In April 1983, seven cases of contact vaccinia infection were identified in Nevada following exposure to a recently vaccinated military dependent. On April 14, the vaccinee, an 11-year-old girl, mistakenly received a smallpox vaccination during immunization clearance for travel to Germany. The vaccinee had a "primary" reaction.

The primary pustule was present when the vaccinee attended a slumber party with seven other girls on April 17. Activities included exchanging and wearing articles of clothing. On April 22, the other seven girls presented at a U.S. Air Force clinic with primary lesions distributed widely on their bodies. The girls were quarantined at their homes for 14 days, during which the lesions resolved. The illnesses were mild. No additional cases were reported. Reported by HA Wesche, Major, USAF, NC, Chief, Environmental Health, Nellis Air Force Base, Nevada; AK Cheng, Col, USAF, MC, Chief, Preventive Medicine Br, Brooks Air Force Base, Texas; Div of Immunization, Center for Prevention Svcs, CDC.

Editorial Note

Editorial Note: This outbreak demonstrates again that there are risks associated with smallpox vaccination and illustrates the relative ease of person-to-person transmission of vaccinia virus. Although these cases were mild, vaccinia infection can be fatal, especially in individuals with compromised immunologic mechanisms. The last reported outbreak of contact-spread vaccinia followed exposure to a recently vaccinated member of the Canadian armed forces in Newfoundland in 1981 (1).

In May 1980, the World Health Organization declared the world free of smallpox. The January 1982 revision of the International Health Regulations removed smallpox from the list of quarantinable diseases. As a result, the revised International Certificate of Vaccination does not include smallpox vaccination. Smallpox vaccination should not be given for international travel.

Civilian smallpox vaccination is now recommended only for laboratory workers directly involved with smallpox virus or closely related orthopox viruses (e.g., monkeypox, vaccinia) (2) and should not be used in attempts to treat or prevent diseases such as herpes. Wyeth Laboratories, the only licensed producer of smallpox vaccine in the United States, discontinued distribution for general use in May 1983 (3).


  1. Laboratory Centre for Disease Control. Vaccinia outbreak--Newfoundland. CDWR 1981;7:29-31.

  2. Immunization Practices Advisory Committee. Smallpox vaccine. MMWR 1980;29:417-20.

  3. CDC. Smallpox vaccine no longer available for civilians--United States. MMWR 1983; 32:387.

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