The risk of a laboratory-acquired infection with vaccinia virus is not known with certainty. However, several laboratory-acquired infections have been reported, including infections with recombinant vaccinia viruses. Because human trials are being conducted with experimental vaccine-HIV recombinant vaccines, it is also possible that other health care workers, such as nurses and physicians, could be exposed to both vaccinia and recombinant vaccinia viruses. Since 1980, the United States Public Health Service has recommended the use of vaccinia vaccine to protect laboratory workers from infection with orthopoxviruses, including persons working with animals infected with orthopoxviruses. The vaccinia vaccine licensed in the United States contains live vaccinia virus, derived from the New York City Board of Health strain of vaccinia.
Vaccine is administered using the multiple puncture technique with a bifurcated needle.
The level of antibody required for protection against vaccinia infections is not known. Laboratory workers who directly handle animals contaminated or infected with vaccinia, recombinant vaccinia, or other orthopoxviruses. However, because a theoretical risk of infection exists, vaccination may be considered for this group. Antibody to vaccinia following vaccination appears to persist for many years. The Public Health Service recommends that persons working with vaccinia, recombinant vaccinia viruses or other non-variola orthopoxviruses be revaccinated every 10 years.