A new report released this week by the General Accounting Office (GAO), a Congressional investigative agency, reveals that childhood vaccines are in short supply nationwide, forcing schools and day care centers to reduce immunization requirements. According to the report, which will be reviewed Tuesday at a hearing of the Senate Health, Education, Labor and Pensions subcommittee, the lack of vaccines increases the possibility that diseases will spread.

The GAO report indicates that 49 states are now rationing more than one vaccine, which the study's authors say may be due to the lack of vaccine manufacturers. Several childhood vaccines are made by only one drug company. Furthermore, researchers involved in the study say that the Centers for Disease Control and Prevention has only a two-month supply of vaccines stockpiled in case of an emergency shortage (a six-month supply of recommended childhood vaccines is required by law).