Chairman Burton has focused his attentions on allegations regarding vaccine safety, many of which are not backed by scientific evidence. Vaccine safety is a critical issue that deserves ongoing oversight. However, there are other issues that need to be addressed as well. Public health experts are increasingly concerned about the fragility of the vaccine supply. At the end of 2001, the United States was experiencing shortages or delays in delivery of vaccines that prevent 10 of the 11 childhood diseases against which children are routinely immunized. Rep. Waxman, along with colleagues in the House and Senate, have asked the General Accounting Office to examine the issue of vaccine supplies.