The ACA, which is still in force, requires all insurance of whatever type issued since 2010 to provide immunizations for free at the point of service, with no co-pays or charges to deductible.  This applies to high deducible insurance, individual plans, employer-sponsored plans, bronze, silver, platinum, etc.  For the uninsured/underinsured (there are a few grandfathered policies that don't cover IZs), people on Medicaid, Native Americans and Alaskan natives, there is the Vaccines for Children program which provides free immunizations.  https://www.cdc.gov/vaccines/programs/vfc/index.html