The present invention belongs to the field of animal health and provides means to study Porcine Reproductive and Respiratory Syndrome (PRRS), a viral disease affecting swine, and for the development of vaccines, therapeutics and diagnostics for the prophylaxis, treatment and diagnosis of PRRS. In a first consideration, the invention relates to a new PRRS virus variant, and, in a second consideration, to a nucleic acid sequence which comprises the genome of an infectious genotype I (EU) PRRS virus clone. Based on this, new PRRS vaccine candidates with improved properties are provided.