MMR Booster Vaccine Names
In the United States, there are two FDA-approved MMR vaccines that can be used as boosters: M-M-R II (Merck) and PRIORIX (GlaxoSmithKline). Both vaccines are fully interchangeable and can be used for the second dose (booster) regardless of which vaccine was used for the first dose 1.
Available MMR Vaccines
M-M-R II (Merck)
- Available in the U.S. since 1978
- The original and most widely used MMR vaccine in the United States 1
- Contains live attenuated measles, mumps, and rubella viruses
PRIORIX (GlaxoSmithKline)
- FDA-approved June 6,2022
- ACIP recommended June 23,2022 1
- Contains live attenuated viruses genetically similar or identical to M-M-R II 1
- Fully interchangeable with M-M-R II for all indications 1
Key Clinical Points
Both vaccines are completely interchangeable for booster doses. The ACIP explicitly states that vaccination should not be deferred when the manufacturer of the previously administered vaccine is unknown or unavailable 1. Studies demonstrate that PRIORIX is safe and immunogenic when administered as a second dose after M-M-R II 1, 2.
Standard Booster Schedule
- First dose: 12-15 months of age
- Second dose (booster): 4-6 years of age 1
Either M-M-R II or PRIORIX can be used for the booster dose, regardless of which vaccine was used initially.
Administration
- Both vaccines: 0.5 mL subcutaneous injection 1
- Both are supplied as lyophilized powder requiring reconstitution
- No preservatives in either formulation 1
The availability of two manufacturers helps safeguard vaccine supply in the United States to maintain measles and rubella elimination and mitigate mumps outbreaks 1.