Give an example of a live vaccine.

• A. MMR
• B. Hepatitis B
• C. Pneumococcal
• D. Inactivated influenza

Answer: (A)

Live vaccines use a weakened form of the pathogen that can still replicate in the body, which helps the immune system recognize the organism and develop a strong, long-lasting response with fewer doses. The MMR vaccine is a classic example because it contains attenuated measles, mumps, and rubella viruses designed to provoke immunity without causing disease in healthy people. Hepatitis B is not live; it’s a recombinant subunit vaccine made from the hepatitis B surface antigen produced in yeast. Pneumococcal vaccines are conjugate or polysaccharide vaccines and are not live. The influenza vaccine given intramuscularly is inactivated; the virus is killed and cannot replicate, so it’s not a live vaccine. Keep in mind that live vaccines are generally avoided in severely immunocompromised individuals and may be contraindicated in pregnancy for certain vaccines.