The invention relates to a mutant Porcine Epizootic Diarrhea Virus (PEDVdN), to methods of producing said PEDVdN, and to compositions comprising the PEDVdN. The invention further relates to methods of stimulating an immune response in a pig comprising administering the PEDVdN, to vaccines comprising the PEDVdN, and to methods for preventing or ameliorating porcine epizootic diarrhoea in a pig.