 Participants will be admitted to the inpatient unit 1 or 2 days before receiving their first dose of the vaccine. While in the inpatient unit, all participants will undergo a medical history review, physical examination, nasal wash, blood collection, pregnancy testing for female participants, and pregnancy prevention counseling. Participants will be discharged from the inpatient unit on Day 7 or possibly later, depending on the results of participants lab tests. An additional study visit will occur at Day 14. 