A peptide-based marker vaccine against Porcine Reproductive and Respiratory Syndrome (PRRS) and a set of immunodiagnostic tests for the prevention, monitoring and control of Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) are disclosed. Vaccine formulations according to various embodiments of the invention contain a mixture of peptides derived from PRRSV GP2, GPS, GP4, or GPS proteins each peptide individually contains a B cell PRRSV neutralizing/receptor binding epitope which is individually linked to an artificial T helper epitope for enhancement of the respective peptides immunogenicity and which can be supplemented with a mixture of peptides representing the T helper epitopes derived from the PRRSV GP4, GPS, M and Nucleocapsid proteins to provide cell mediated immunity. Such viral peptide compositions are prepared in an acceptable delivery system as vaccine formulations and can provide cross protection of PRRSV antibody free pigs from infection upon PRRSV challenge.
