Research progress in the development of porcine reproductive and respiratory syndrome virus as a viral vector for foreign gene expression and delivery

INTRODUCTION: Porcine reproductive and respiratory syndrome (PRRS) is an infectious disease of swine characterized by respiratory disorders in growing and finishing pigs and reproductive failure in pregnant sows. PRRSV has been recognized as one of the most economically significant pathogens affecting the global pig industry. AREAS COVERED: Currently, commercially available vaccines, including traditional killed virus (KV) vaccines and modified live virus (MLV) vaccines, are the cardinal approaches to prevent and control porcine reproductive and respiratory syndrome virus (PRRSV) infection. However, the protective efficacy of these vaccines is not satisfactory, resulting in the continuous evolution and recurrent appearance of the virus as well as the emergence of new variants. A safe and effective vaccine against PRRSV is in dire need. Here, we review the research progress in recent years in the development and use of PRRSV as a viral vector to express foreign genes, and their potential application in gene delivery and vaccine development. EXPERT OPINION: The potential of using PRRSV-based vectors to express multiple antigens would be particularly instrumental for the development of a new generation of multivalent vaccines against PRRSV and other porcine viruses.