Where do vaccine-derived polioviruses come from, and should I be concerned if there is a case in the United States?
VDPVs can cause outbreaks in countries where vaccine coverage with OPV is low. Long-term excretion can also occur in people with certain immunodeficiency disorders. Because OPV has not been used in the United States since 2000 and vaccine coverage with IPV is high, it is unlikely that any vaccine-derived poliovirus (VDPV) seen in the United States would become widespread. Also, polio vaccination protects people against naturally occurring polioviruses and vaccine-derived polioviruses.
