if by any mistake baby gets same vaccine double times...does it causes any danger or infection to baby..?

A. It’s not a matter of concern. There are times when a child may get an extra vaccine dose. For example, sometimes it is not clear what vaccines a child may have gotten in the past. In that case, vaccinating the child to make sure he or she is fully protected far outweighs any risk of side effects. Your daughter may experience redness, swelling, or soreness after extra shots. But, children who get extra doses of any vaccine are, for the most part, at no extra risk than children who follow the regular schedule. All in all, the end result should only be more of a boost to her immune system. Extra doses really are "extra" doses. They do not count as part of the regular schedule. She is likely to still need the next doses of vaccines given at their usual times.