Which of the Following Is Not a Requirement of an Effective

Which of the following is not a requirement of an effective vaccine?

A) The components of the vaccine should induce protective immune responses
B) The host should mount a memory response that has the capacity to respond if the pathogen is encountered at a later time
C) The vaccine should induce only mild disease
D) The vaccine should be biologically stable
E) The cost to produce and administer the vaccine should be minimized to promote effective use in target populations