Which of the following best defines an attenuated vaccine?

Which antigen processing and presentation pathway is more strongly engaged by replicating attenuated viral vaccines than by nonreplicating inactivated vaccines, and why does this matter for immunity?

A clinic has 1,000 vaccine doses available. Option A is a live attenuated vaccine requiring a single dose per person with 95% efficacy. Option B is an inactivated vaccine requiring two doses per person (prime and booster) with 85% efficacy once the two-dose series is complete. If the clinic uses only Option A, how many people are expected to be protected? If the clinic uses only Option B (administering all doses as boosters where needed), how many people are expected to be protected? Choose the correct numerical comparison.

An HIV-positive patient with a CD4 count of 150 cells/µL requests a measles-mumps-rubella (MMR) vaccine (live attenuated). Based on safety considerations, which is the best evidence-based recommendation?

You are engineering an attenuated viral vaccine and must minimize reversion risk. Which multi-pronged genetic strategy best balances retention of limited replication and reduced chance of reversion to pathogenicity?