Aventis Pasteur has recalled four lots of IMOVAX rabies vaccine because of a potential public health threat.

During a recent quality assurance test of the inactivated viral vaccine, the manufacturer detected the presence of live Pitman-Moore virus in a single lot. The contaminated lot was not distributed, but as a precautionary measure, four lots produced concurrently were recalled. Those lots were distributed in the United States from Sept. 23, 2003, to April 2, 2004, and were numbered X0667-2, X0667-3, W1419-2, and W1419-3. Additional lots were distributed internationally, and the manufacturer is working with regulatory authorities to trace those lots.

According to the national Centers for Disease Control and Prevention, the recalled lots passed all FDA-approved release tests, including testing to confirm the absence of live virus: "These test results suggest that any potential risk to those vaccinated with recalled vaccine is likely to be low." No unusual adverse events associated with the recalled vaccine have been reported.

Health care providers should contact persons who received recalled vaccine and implement the precautionary treatment recommended by the manufacturer. The treatment is outlined on the CDC's Web site, www.cdc.gov/mmwr/preview/mmwrhtml/mm53d402a1.htm. Individuals who have received rabies vaccine between Sept. 23, 2003, and April 2, 2004, should contact their health care providers to determine whether they were exposed to recalled vaccine. If necessary, the health care providers will begin treatment. Vaccine distributors and health care providers who have doses of the recalled lots should contact Aventis Pasteur about disposing of them. For information about the recall, call (800) 835-3587, or visit www.vaccineshoppe.com.

Individuals who have begun the rabies vaccination series for pre- or postexposure prophylaxis must complete the series on time. Information on preventing rabies in humans is available at www.cdc.gov/mmwr/preview/mmwrhtml/00056176.htm.

More information on the recall is available at www.cdc.gov/ncidod/dvrd/rabies/ques&ans/faqs-generalinfo.htm.