What does a live vaccine do?

What does a live vaccine do?

• A. It mimics a microorganism antigenically, but does so without producing disease in healthy individuals.
• B. It causes disease in healthy individuals to stimulate immunity.
• C. It uses only inactivated toxins.
• D. It provides lifetime immunity after a single dose.

Answer: (B)

Live vaccines use a weakened form of the microorganism that can still replicate in the body but does not cause disease in healthy individuals. Because the attenuated organism closely mimics a real infection, it presents the immune system with authentic antigens and stimulates a broad, durable response, engaging both antibodies and T-cells. This often yields strong, long-lasting immunity with fewer doses compared to inactivated vaccines. Some vaccines may need boosters later, and these vaccines are generally not given to people with significant immune compromise. The other ideas don’t fit the concept: vaccines that use only inactivated toxins are toxoids, not live vaccines; and vaccines are not guaranteed to provide lifetime immunity after a single dose.

Live vaccines use a weakened form of the microorganism that can still replicate in the body but does not cause disease in healthy individuals. Because the attenuated organism closely mimics a real infection, it presents the immune system with authentic antigens and stimulates a broad, durable response, engaging both antibodies and T-cells. This often yields strong, long-lasting immunity with fewer doses compared to inactivated vaccines. Some vaccines may need boosters later, and these vaccines are generally not given to people with significant immune compromise. The other ideas don’t fit the concept: vaccines that use only inactivated toxins are toxoids, not live vaccines; and vaccines are not guaranteed to provide lifetime immunity after a single dose.