Immunity, Vaccines, and Cancer Practice Test 2026 – Complete Exam Prep

Inactivated vaccines deliver antigen without replication, so the immune stimulus is less robust and shorter-lived than with live attenuated vaccines. Because they don’t replicate, the initial exposure often produces lower antibody titers and weaker memory responses, meaning protection can wane over time. Booster doses repeatedly re-expose the immune system, re-stimulating memory B and T cells and boosting antibody levels, which helps maintain long-term protection. Live attenuated vaccines, by replicating in the body, tend to produce stronger, more durable immunity with fewer doses, so they don’t typically require boosters as often as inactivated ones. That’s why boosters are typically needed for inactivated vaccines to sustain long-term immunity.