From Public Health England:
With single vaccines, children would need 6 separate injections:
3 primary doses - 1 measles, 1 mumps, 1 rubella
3 pre-school boosters
Each injection can be uncomfortable and the act of immunisation is sometimes distressing for children.
Single vaccines are less safe than MMR because they leave children vulnerable to dangerous diseases for longer. Giving 3 separate doses at spaced out intervals would mean that, after the first injection, the child still has no immunity to the other 2 diseases.
Given the benefits of combining the measles, mumps, and rubella vaccines into a single MMR (measles, mumps, and rubella) vaccine, why don't we see similar packaging more often? Why aren't other vaccines similarly combined?