Update: potential exposures to attenuated vaccine strain Brucella abortus RB51 during a laboratory proficiency test--United States and Canada, 2007.

In November 2007, New York State Department of Health (NYSDOH) officials notified CDC of potential exposures to attenuated vaccine strain Brucella abortus RB51 (RB51) in multiple clinical laboratories that participated in a Laboratory Preparedness Survey (LPS) proficiency test. NYSDOH conducted a survey of participating laboratories and identified 17 laboratories that reported handling the RB51 sample in a manner placing lab workers at potential risk for exposure. Subsequently, CDC recommended that public health officials conduct a review of biosafety practices at all LPS-participating laboratories to identify any additional RB51 exposures. This report summarizes the results of investigations in 36 states, two cities, one county, and the District of Columbia. As of January 14, 2008, follow-up by public health officials with LPS-participating laboratories throughout the United States identified a total of 916 laboratory workers in 254 laboratories with potential RB51 exposure. The results highlight the need for routine adherence to recommended biosafety practices when working with infectious organisms, particularly during widespread infectious-disease events, including bioterrorism attacks.