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In 1963, Dr. John Enders and colleagues, who had transformed the Edmonston-B strain of the measles virus to a vaccine, got it licensed in the United States.

In 1968, an An improved and weaker measles vaccine, created by Maurice Hilleman and colleagues in 1968, began to be distributed in the United States. This vaccine was called the Edmonston-Enders (formerly Moraten) strain and has been the only vaccine used in the United States since.

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