Prevention Through Affordable Access Act of 2009 - Amends title XIX (Medicaid) of the Social Security Act to revise requirements for the best price component of the formula for determination of the Medicaid rebate for a covered single source outpatient drug or a covered innovator multiple source outpatient drug. (Under current law, best prices shall not take into account prices that are merely nominal in amount.)
Revises the list of entities to which sales by a manufacturer of covered outpatient drugs at nominal prices shall be considered to be sales at a nominal price, or merely nominal in amount (and thus excluded from computation of the best price for such drugs).
Adds to such list any entity that is: (1) operated by a health center of an institution of higher education, primarily for its students (university-based clinic); or (2) a public or private nonprofit entity that provides family planning services under the Public Health Service Act (safety-net clinic).