S.2476: A bill to amend the Public Health Service Act to improve immunization rates by increasing the supply of vaccines.

Improved Vaccine Supply Act - Amends the Public Health Service Act to require the Secretary of Health and Human Services, acting through the Director of the Centers for Disease Control and Prevention (CDC), to develop a plan for the purchase, storage, and rotation of a six-month supply of vaccines routinely recommended for children and adults and vaccines that contribute to public health preparedness efforts.

Requires the Secretary to: (1) fully implement the plan; and (2) require manufacturers of vaccines included in such supply to provide at least one year notice of a discontinuance of the manufacture of a vaccine.