There is some language in legislation that was approved by the Senate Health, Education, Labor and Pensions (HELP) committee and announced on July 15 that points to the possibility of mandatory vaccinations:
"Authorizes a demonstration program to improve immunization coverage. Under this program, CDC will provide grants to states to improve immunization coverage of children, adolescents, and adults through the use of evidence-based interventions. States may use funds to implement interventions that are recommended by the Community Preventive Services Task Force, such as reminders or recalls for patients or providers, or home visits."
This language is found in the first paragraph of page 14 of a summary of the legislation that is found on the Senate committee's website. Here is the link to the 22 page document:
http://help.senate.gov/Maj_press/2009_07_15_b.pdf