Why do they combine vaccines?

Combination Vaccines: So that you do not have to have too many shots.There have been many combination vaccines and it helps in immunising kids and adults with fewer shots, like dpt, mmr, etc are yhree vaccines in one shot.

It makes sense: They have worked for decades to come up with vaccines that not only work given separately but also when combined. Not all early preparations did so.A big hassle to protecting large numbers in the world is the number of shots, supplies (needles, syringes), refrigeration & nurse time. When protecting tens of millions of people every shot you combine increases the chance more people will get them.