Public health response to varicella outbreaks--United States, 2003-2004.

Since introduction of varicella vaccine in 1995, incidence of varicella has decreased as vaccination coverage has increased. Nevertheless, varicella outbreaks continue to occur, even among populations with high vaccination coverage. Although varicella typically is mild, the outbreaks can last for several months and be challenging and costly for health departments to control. In 2005, CDC conducted a national survey to determine the distribution and extent of reported varicella outbreaks during 2003-2004 and the public health response. This report summarizes the results of that survey, which indicated that varicella outbreaks are still common and that health jurisdictions are responding to these outbreaks, although they have varying definitions and guidelines for varicella-outbreak management.