Definition of Booster shot

Booster shot: An additional dose of a vaccine needed periodically to 'boost' the immune system. For example, a booster shot of the tetanus and diphtheria (Td) vaccine is recommended for adults every 10 years.


Last Editorial Review: 3/19/2012

Search MedTerms:


Back to MedTerms online medical dictionary A-Z List
Pill Identifier Tool

Need help identifying pills and medications?
Use the pill finder tool on RxList.