The present invention relates to a poxvirus vector comprising a nucleic acid sequence encoding a fusion protein comprising: (i) a peanut allergen selected from list consisting of at least two peanut allergens from ara h 1, ara h 2, ara h 3, ara h 4, ara h 5, ara h 6. ara h 7, ara h 8, ara h 9, ara h I O and ara h I I or a derivative or part thereof having at least 70% sequence identity thereto, and (ii) a profeasome degradation tag to enhance intracellular degradation of the fusion protein. Methods of desensitizing or inducing tolerance to a peanut allergen and/or suppressing an allergic response to a peanut allergen are also disclosed.
