California counties large and small are preparing for the transition of thousands of low-income Californians with HIV/AIDS from a federal safety-net program to other programs under the Affordable Care Act.

The federal Ryan White HIV/AIDS Program, enacted in 1990, provides a broad spectrum of therapies, drug remedies and primary care to more than 500,000 people each year, according to HHS’ Health Resources and Services Administration, which oversees the program.

The Ryan White Program is a payer of last resort, meaning that if a patient is eligible for another health plan or program, such as Medi-Cal, the state’s Medicaid program, or the Low Income Health Program in California, that service must be used first.

An estimated 55% of HIV-positive individuals using Ryan White funds are expected to…