Use of Vaccinia Virus Smallpox Vaccine in Laboratory and Health Care Personnel at Risk for Occupational Exposure to Orthopoxviruses

What is currently recommended?

In 2001, the Advisory Committee on Immunization Practices approved revised recommendations that laboratory and health care personnel occupationally exposed to vaccinia virus, recombinant vaccinia viruses, and other orthopoxviruses that can infect humans be vaccinated with Dryvax smallpox vaccine.

Why are the recommendations being modified now?

In 2007, ACAM2000 was licensed by the U.S. Food and Drug Administration and replaced Dryvax as the only smallpox vaccine available for use in the United States. The evidence supporting routine vaccination with ACAM2000 for laboratory personnel at risk for occupational exposure to orthopoxviruses was evaluated using the Grading of Recommendations, Assessment, Development, and Evaluation framework and determined to be type 2 (moderate level of evidence); the recommendation was designated as a Category A recommendation.

What are the new recommendations?

Routine vaccination with ACAM2000 is recommended for laboratory personnel who directly handle 1) cultures or 2) animals contaminated or infected with replication-competent vaccinia virus, recombinant vaccinia viruses derived from replication-competent vaccinia strains (i.e., those that are capable of causing clinical infection and producing infectious virus in humans), or other orthopoxviruses that infect humans (e.g., monkeypox, cowpox, and variola) (recommendation category: A, evidence type 2). Health care personnel (e.g., physicians and nurses) who currently treat or anticipate treating patients with vaccinia virus infections and whose contact with replication-competent vaccinia viruses is limited to contaminated materials (e.g., dressings) and persons administering ACAM2000 smallpox vaccine who adhere to appropriate infection prevention measures can be offered vaccination with ACAM2000 (recommendation category: B, evidence type 2).