Circulating vaccine-derived polioviruses The oral polio vaccine, while highly effective, has the disadvantage that it contains a live virus which has been attenuated so that it cannot cause severe illness. The vaccine virus is excreted in the stool, and in under-immunized communities it can spread from person to person. This is known as circulating vaccine-derived poliovirus (cVDPV) or more simply as variant poliovirus.
Circula!ting vaccine-derived polioviruses The oral polio vaccine, while highly effective, has the disadvantage that it contains a .live virus which has been attenuated so that it cannot cause severe illness. The vaccine virus is excreted in the stool, and in under-immunized communities it can sp?read from person to person. This is known as circulating vaccine-derived poliovirus (cVDPV) or more simply as variant pol.iovirus.