Vaccine is a principal and highly cost-effective medical method on controlling infectious diseases and improving population health.Various vaccines are badly needed in the low-income countries along the Belt and Road.With the good quality to reach WHO prequalification standard,and the abundant capacity to fulfill the demand from market aboard,upon the platform of China-proposed "the Belt and Road Initiative",the vaccines manufactured in China are exporting to counties worldwide.The independent innovative vaccines' R&D system,which fruited a series of innovative infectious diseases vaccines (EV71 vaccine,slPV,HEV,Ebola vaccine,etc.) to be launched in Chinese market,indicates that China has developed rapidly from "a great vaccine-production country" to "a powerful vaccine-innovation country".The implementation of National Innovation-driven Development Strategy would further push forward the development and internationalization process of Chinese innovative vaccines.Therefore,the China-invented vaccines will make an important role in the prevention and control of infectious disease in various countries and become one of the most powerful weapons in fighting the global epidemics event in the future.

In April 2016, the Global Polio Eradication Initiative (GPEI) adjusted its polio vaccination strategy, converting trivalent oral polio vaccine (tOPV) into bivalent oral polio vaccine (bOPV), and withdrawing type 2 oral polio vaccine (OPV2) globally. However, after the withdrawal of OPV2, there were many outbreaks of type-2 circulating vaccine-derived poliovirus (cVDPV2) in Asia and Africa. In order to eradicate poliovirus completely, GPEI launched the research and development of the novel serotype 2 oral polio vaccine (nOPV2) in 2010 and considering whether it is necessary to reuse OPV. This paper summarizes the epidemiological situation of cVDPV2 before and after OPV2′s withdrawal, the related factors affecting the reuse of OPV and the related research progress of nOPV2.

In April 2016, the Global Polio Eradication Initiative (GPEI) adjusted its polio vaccination strategy, converting trivalent oral polio vaccine (tOPV) into bivalent oral polio vaccine (bOPV), and withdrawing type 2 oral polio vaccine (OPV2) globally. However, after the withdrawal of OPV2, there were many outbreaks of type-2 circulating vaccine-derived poliovirus (cVDPV2) in Asia and Africa. In order to eradicate poliovirus completely, GPEI launched the research and development of the novel serotype 2 oral polio vaccine (nOPV2) in 2010 and considering whether it is necessary to reuse OPV. This paper summarizes the epidemiological situation of cVDPV2 before and after OPV2′s withdrawal, the related factors affecting the reuse of OPV and the related research progress of nOPV2.