I briefly mentioned this "What If?" coin in a "Modern US Coins" thread about the lack of commemorative US dimes, but believed it deserved a more complete post in slightly longer form...In April 1955, Senator Frank Aloysius Barrett (R-WY) introduced a bill calling for a "special 10-cent piece in recognition of the recent discovery of a vaccine by Dr. Jonas E. Salk for the prevention of poliomyelitis." Representative Charles Samuel Gubser (R-CA) introduced a House Concurrent Resolution in May 1955, that proposed the same coin.
Jonas Salk, MD developed the first viable/effective vaccine against poliomyelitis (aka, Infantile paralysis and polio); his vaccine used a protocol that inactivated (killed) the virus before it was injected. His research was funded by the National Foundation for Infantile Paralysis (later, the March of Dimes ); the Foundation was created by President Franklin Delano Roosevelt (FDR), a polio sufferer (his diagnosis at the time, though some now believe it was incorrect). He announced the new Foundation in September 1937, with leadership details fleshed out by January 1938.
From the language in the bill/resolution, the proposed coin was to be a limited release circulation coin - most likely a one-year type. No mintage for the commemorative piece was stated; it was to be set by the Secretary of the Treasury. Also, no sponsor/beneficiary of the coin was identified and no discussion of ordering the coins and/or paying for them was included. These are all signs of a circulation coin proposal vs. one intended as a fundraiser for a private group.
The language is not clear as to whether the Salk Dime would temporarily replace the Roosevelt Dim, or circulate alongside it. Personally, I think if would have been the most impactful if the two closely-related coins were issued concurrently.
The bill and resolution were each referred to the Committee on Banking and Currency, but were not reported out by the Committee for further consideration.
So, no replacement for, or companion piece to, the
Roosevelt dime to honor the man behind the development of the first viable polio vaccine was approved. It was good to see him honored on the 2015 March of Dimes 75th Anniversary commemorative silver dollar and for the Mint to have further linked such a commemorative piece to FDR - an important ally - with special editions of the
Roosevelt dime.
2015 March of Dimes Commemorative Silver Dollar

FDR is the front portrait on the obverse (left), with the portrait of Dr. Jonas Salk in the rear.
For more of my posts about commemorative coins and medals, check out:
Commems Collection.