Which of the following vaccines is not a live vaccine?

• A. MMR
• B. Varicella
• C. DTap
• D. Sabin polio vaccine

Answer: (C)

The key idea is the difference between live (attenuated) vaccines and non-live (inactivated or subunit) vaccines. Live vaccines use a weakened form of a pathogen that can replicate in the body, often producing a strong and durable immune response. Non-live vaccines do not contain replicating organisms; they use inactivated toxins or purified parts of the pathogen to stimulate immunity, usually with a lower risk of causing disease and often requiring boosters.

Among the options, vaccines like MMR, Varicella, and Sabin polio vaccine are live attenuated vaccines; they contain weakened forms of the virus that can still replicate in the body and stimulate immunity. The one that is not a live vaccine is the diphtheria-tetanus-acellular pertussis vaccine. It contains inactivated diphtheria and tetanus toxins (toxoids) and purified components of pertussis rather than a live organism, so it does not replicate and is considered a non-live vaccine.