- Female of childbearing potential (except subjects in a monogamous same sex relationship), must use an effective birth control for the 28 days prior to immunization and must agree to continue employing adequate birth control measures from Day 0 (first immunization) until at least 60 days post-second immunization and must have no plan to become pregnant from Day 0 (first immunization) until at least 60 days post-second immunization. Highly effective birth control includes hormonal contraceptives (e.g., injectable, topical [patch], estrogenic vaginal ring, etc.), intra-uterine device (IUD), abstinence (confirmed by Investigator), or male condom plus spermicide. Abstinent subjects should be asked what method(s) they would use, should their circumstances change, and subjects without a well-defined plan should be excluded