Are Extra Doses of Vaccines Harmful?

Learn whether it is harmful to give extra doses of the routine childhood vaccines, and how you can prevent that from happening. Dr. Shari Nethersole, a physician at the Boston Children's Hospital weighs in.
girl getting shot

My ex-husband took our son to the doctor. They gave him a round of shots that he had already been given a year ago, because they didn't have complete shot records. Is this harmful to him?

More: Are "Extra" Immunizations Dangerous?


I don't know the age of your son, so I can't be sure of which shots he was given, but, in general, it is not harmful to give extra doses of the routine childhood vaccines. The schedule for these vaccines was devised to try and make sure that most people would be protected against those diseases with the smallest number of doses. An extra dose will only stimulate the immune system to be even more protective.

Remember that vaccines used in this country are incredibly safe. There is no increased risk of side effects in an otherwise healthy child. In fact, when children come to this country from overseas, and the shot record cannot be found, the official recommendation of the CDC (Centers for Disease Control) is to start the series over again. The major drawback for the patient is the discomfort of getting the extra injections.

little girl getting vaccine shot

Parents should maintain some sort of immunization booklet for their children, so that this information can be shared to a new provider when families move. Currently, in some communities, a computerized immunization record has been developed that can be viewed by schools and health care providers in that community in order to verify immunization doses and dates.

How much do you know about childhood vaccination schedules, and general vaccine facts? Take the Vaccines and Immunizations Quiz.

