By Ethan Covey
The rate of vaccine-derived polioviruses (VDPVs) increased during January 2017 to June 2018, compared with the previous report period of January 2016 to June 2017. VDPVs typically circulate in areas of low population immunity, or during outbreaks, according to the CDC.
During the 2017-2018 reporting period, new circulating VDPVs (cVDPVs) were identified in the Democratic Republic of the Congo, Kenya, Nigeria, Papua New Guinea and Somalia (MMWR Morb Mortal Wkly Rep