The invention relates generally to the field of virology. More particularly,the present invention relates to methodsfor determining the effect of a viral inactivation procedure on theantigenicity of the inactivated virus. In particular for a virus thatis a member of the family Arteriviridae or Coronaviridae or Asfarviridae, inparticular for Porcine Reproductive and RespiratorySyndrome Virus (PRRSV). The invention further provides methods to determinethe antigenicity of an inactivated virus as well asmethods to screen for anti-viral compounds using any one of the aforementionedmethods Methods of using the inactivated andimmunogenic virus thus obtained, in particular in the manufacture of a vaccineare also provided by the present invention.
