Why Are Booster Shots Necessary?
Some vaccines, such as tetanus and pertussis, don’t provide lifelong immunity. Booster shots are necessary to raise (boost) immunity in high-risk age groups. The practice of administering regular booster shots also keeps as large a portion of the population as possible vaccine-protected. Such vaccine protection establishes “herd”immunity. This refers to how an individual has a lowered risk of catching a disease, not specifically because he or she has been immunized, but because so many others have been immunized that there are few people left who can spread the disease.
