A liquid or liquid-frozen composition comprising: a modified vaccinia Ankara (MVA) virus or variant or derivative thereof and mannitol, wherein mannitol is the sole stabilization agent of the composition. The mannitol may provide a stabilizing effect at 0 to +10° C. or in a liquid-frozen composition, for example between &minus10° C. and &minus30° C. or between &minus20° C. and &minus23.5° C. The MVA may be used as a vaccine or for use in gene therapy, virotherapy, immunotherapy, or cancer therapy in a mammal, preferably a human.