Participants record their temperature and symptoms in a diary card for 7 days following each injection. They return to the clinic 2 to 3 days after each injection and then 2 weeks after each injection until study week 10. Additional follow-up visits are then scheduled at weeks 12, 24, 38, and 52. At each visit, participants provide a blood and urine sample for testing and have their vital signs, and lymph nodes checked, their weight measured, and their symptoms reviewed. Additional laboratory tests may be requested between visits.