42 CFR § 406.5 - Basis of eligibility and entitlement.
(1) Are age 65 or over, or
(2) Have received social security or railroad retirement disability benefits for 25 months; or
(b) Premium hospital insurance. Many individuals who are age 65 or over, but do not meet the requirements set forth in subpart B of this part, and certain individuals under age 65, may obtain the benefits by paying a premium. Section 406.20 of this part explains the requirements individuals must meet to obtain premium hospital insurance.