This is a phase I, open label, dose escalation trial to assess the safety and immunogenicity of the ChAdOx2 and MVA HAV vaccines against Mycobacterium avium subspecies paratuberculosis (MAP) in healthy volunteers~There will be 5 study groups with a total of 28 volunteers. ChAdOx2 HAV will be administered intramuscularly as a single vaccination at 3 different doses: 5x10^9 vp (group 1), 2.5x10^10 (group 2) and 5x10^10 vp (group 3) and as a prime vaccine in group 6 (prime/boost group). MVA HAV will be administered intramuscularly as a single vaccination at 2 different doses: 5x10^7 pfu (group 4), 2x10^8 pfu (group 5) and as a boost vaccine in group 6 (prime/boost group)~Vaccination of groups will be sequential from Group 1 to Group 6 with interim safety reviews prior to dose escalation~Volunteers will be recruited and undergo screening visits, vaccination and clinic visits post-vaccination at the trial site. Blood samples for safety and immunology purposes will be performed on the visit time points indicated in the schedule of attendances.~Safety will be assessed by the frequency, incidence and nature of adverse events and serious adverse events arising during the study.
A phase I dose escalation study to assess the safety and immunogenicity of the candidate vaccines ChAdOx2 HAV and MVA HAV in healthy volunteers.~Volunteers will be recruited and vaccinated in Oxford, England.~All vaccinations will be administered intramuscularly. Three different doses of the ChAdOx2 HAV will be tested (5x10^9 vp, 2.5x10^10 vp and 5x10^10vp). MVA HAV will be assessed at 2 different doses (5x10^7 and 2x10^8 pfu)~The total duration of the study will be 52 weeks from the day of enrolment for volunteers receiving ChAdOx2 HAV only, 12 weeks for volunteers receiving MVA HAV only and 20 weeks for volunteers receiving ChAdOx2 HAV and MVA HAV.