Randomized, Open-label Phase II Trial to Assess the Safety and Immunogenicity of MVA-BN Smallpox Vaccine in Immunocompromised Subjects With HIV Infection

The main purpose of this clinical trial is to generate additional safety data in a highly immunocompromised population. HIV-infected persons are considered excellent candidates to represent the highly immunocompromised population for enrolment in this trial. Additionally, the immune system\'s response (protection against smallpox as measured by the amount of antibodies produced) following injections of MVA-BN® smallpox vaccine will be evaluated. All participants in this trial will be randomly and evenly assigned to one of three groups to receive two, three or four injections. Group 1 will receive the standard regime consisting of one dose at each vaccination time point, Group 2 will receive two doses at each vaccination time point and Group 3 will receive a booster vaccination 12 weeks after the standard vaccination schedule with MVA-BN® smallpox vaccine. Participation in the trial is scheduled to last up to 75 weeks.