What would you expect to happen to the incidence and prevalence of a disease if a new drug were discovered that prevented mortality from the disease but did not cure it?

Incidence unchanged, prevalence increases.

Explanation:

Disease can be caused by the pathogens like virus, bacteria, fungi and plasmodium. The infection fro the disease also depends on the immunity of the individuals.

Discovery of the drug requires different experiment and observations. The drug that prevents the mortality but not able to cure the disease. This do not change the disease incidence but might not able to the increase in the prevalence of the disease.

Thus, the answer is incidence unchanged, prevalence increases.

answer; teamwork;