- Any acute or chronic medical condition that, in the opinion of the investigator, would render vaccination unsafe, interfere with the evaluation of responses, or render the subject unable to meet the requirements of the protocol. These conditions include, but are not limited to: history of significant renal impairment (dialysis and treatment for kidney disease, including diabetic and hypertensive kidney disease); subjects with diabetes mellitus, well-controlled with oral agents may enroll as long there has been no dosage increase within the past 6 months; insulin-dependent diabetes is excluded; cardiac insufficiency, if heart failure is present (New York Heart Association Functional Class III or IV); an arteriosclerotic event during the 6 months prior to enrollment (e.g., history of myocardial infarction, stroke, recanalization of femoral arteries, or transient ischemic attack).