If children do not have protection against all three of these diseases, we run the risk of the resurgence of the infections. This means not just measles outbreaks, but, for example, the return of babies born with terrible defects as a result of congenital rubella syndrome, or of children becoming deaf following mumps. Taking all these points together, there is no reason to make single vaccines available and every reason not to. Despite exhaustive research to test the possibility that MMR may be linked to side effects like autism, no evidence has been found that it is linked with these conditions. Introducing single vaccines would fly entirely in the face of all the evidence, and would therefore probably serve only to further undermine public confidence in vaccines.
Single vaccines leave children vulnerable to the diseases for a longer period of time.