Lyophilized IMVAMUNE® (1x10^8 TCID50) Versus Liquid IMVAMUNE® (1x10^8 TCID50) Administered Subcutaneously and a Lower Dose Liquid IMVAMUNE® (2x10^7 TCID50) Administered Intradermally

Inclusion Criteria

Inclusion criteria that must be met prior to the initial vaccination:

• At least 18 years of age and born after 1971.
• Read, signed, and dated informed consent document.
• Available for follow-up for the planned duration of the study (6 months after last immunization).
• Acceptable medical history by screening evaluation and limited physical assessment.
• If the subject is female and of childbearing potential, negative serum pregnancy test at screening and negative urine or serum pregnancy test within 24 hours prior to vaccination.
• If the subject is female and of childbearing potential, she agrees to use acceptable contraception, and not become pregnant for 28 days following the last vaccination:
• A woman is considered of childbearing potential unless post-menopausal (greater than or equal to 1 year) or surgically sterilized (tubal ligation, bilateral oophorectomy, or hysterectomy).
• Acceptable contraception methods are restricted to effective devices [intrauterine devices (IUD)s, NuvaRing®] or licensed hormonal products with use of method for a minimum of 30 days prior to vaccination, abstinence from sexual intercourse with men (vaginal penetration by a penis, coitus), and monogamous relationship with a vasectomized partner.
• Negative enzyme linked immunosorbent assay (ELISA) for human immunodeficiency virus (HIV).
• Alanine aminotransferase (ALT) 140 mm Hg) or are on antihypertensive medication, and/or c. have a family history of coronary heart disease in male first-degree relative (father or brother) <55 years of age or a female first-degree relative (mother or sister) <65 years of age
• High-dose steroid use for greater than 2 weeks duration within three months prior to vaccination and current use of immunosuppressive medication
• Corticosteroid nasal sprays are permissible
• Persons who are using a topical steroid can be enrolled after their therapy is completed
• Inhaled steroids for asthma are not permissible
• Medical or psychiatric condition or occupational responsibilities that preclude subject compliance with the protocol
• Any history of illegal injection drug use
• Receipt or planned receipt of inactivated vaccine from 14 days prior to the first vaccination through 14 days post second vaccination
• Receipt or planned receipt of any other live attenuated vaccine within 30 days prior to the first vaccination through 30 days post second vaccination
• Use of any other experimental agent within 30 days prior to vaccination and for the duration of the study
• Receipt of blood products or immunoglobulin within six months prior to vaccination
• Donation of a unit of blood within 56 days prior to vaccination and prior to Visit 6
• Acute febrile illness (greater than or equal to 100.4 degrees Fahrenheit) on the day of vaccination
• Pregnant or lactating women
• Eczema of any degree or history of eczema
• Active atopic dermatitis, active exfoliative skin disorders/conditions, current Varicella zoster, or any acute skin disorders of large magnitude, e.g., laceration requiring sutures, burn greater than 2×2 cm
• Any condition that, in the opinion of the investigator, might interfere with study objectives
• Known allergy to IMVAMUNE® vaccine
• Known allergy to egg or aminoglycoside (including gentamicin)
• Study personnel

Exclusion criteria that apply prior to the second vaccination:

• Continued inflammation (erythema and/or induration) graded as moderate or severe at the site of the initial vaccination
• History of immunodeficiency
• Known or suspected impairment of immunologic function including, but not limited to, clinically significant liver disease, diabetes mellitus, or moderate to severe kidney impairment
• Malignancy not including squamous cell skin cancer or basal cell skin cancer unless at the vaccination site or history of skin cancer at the vaccination site
• Active autoimmune disease

a. Persons with vitiligo or thyroid disease (e.g., taking thyroid hormone replacement) are no