CDC and the Advisory Committee on Immunization Practices Smallpox Vaccine Safety Working Group (ACIP SVS WG; subsequently referred to in the text as “working group”) have placed a high priority on safety in the national smallpox vaccination program. When safety concerns have arisen, CDC and the working group have responded promptly, as evidenced by the emergency meeting of the full Advisory Committee on Immunization Practices and the working group on March 28, 2003. The committee was reassured that CDC and the working group reported in a timely fashion and conducted further evaluation of the cardiac adverse events that came to light in March. The committee also commends CDC and the working group for modifying screening and education materials when it was recognized that there could possibly be an association between smallpox vaccination and the development of cardiac adverse events, and for communicating these changes to state and local partners in a rapid fashion. The committee notes that the working group has described CDC as being professional, timely with data, and responsive in their interactions with the working group (Neff, 2003).

As has been stated before, the charge of the working group is to (1) evaluate data on vaccine safety and the system for monitoring, treatment, and response and (2) monitor safety data for vaccinia immune globulin (VIG) and cidofovir made available under oversight of the U.S. Food and Drug Administration (FDA) through investigational new drug (IND) protocols (ACIP SVS WG, 2003a).

The committee appreciated receiving information on the operating procedures of the working group (ACIP SVS WG, 2003b). This helped reduce some of the confusion about how the working group was organized and structured. The Summary of the March 20-21, 2003 meeting of the working group by the working group chairpersons (ACIP SVS WG, 2003a) helped address many of the committee’s questions and concerns expressed in previous reports (IOM, 2003b, 2003c). The committee was heartened to see clear descriptions of the case definitions for specific adverse events, trigger points for action on specific events, and actions that should be taken in response to specific triggers.

In assessing trigger points, the working group is (1) identifying appropriate data sets for use in estimating expected incidence, (2) developing statistical reference rates, and (3) determining what action should occur in response to triggers (ACIP SVS WG, 2003a). The working group has developed case definitions, trigger events, trigger points, and responding actions for neurologic, dermatologic, and cardiac adverse events; they also have developed case definitions, trigger points, and responding actions for different types of inadvertent inoculation (e.g., resulting from pregnancy, im-