In 1979, the U.S. Food and Drug Administration (FDA) licensed the RA 27/3 (human diploid fibroblast) strain of rubella vaccine (Meruvax II by Merck); all other strains were discontinued.

Merck’s combined trivalent MMR as well as the combined measles and rubella vaccine (M-RVax) developed by Maurice Hilleman and colleagues, was licensed by the U.S. government in 1971, and is still in use today.

Combination vaccines hold many advantages including reduced need for several injections, therefore, reducing the incidence of vaccination site reaction.