Notes from the Field: Widespread Transmission of Circulating Vaccine-Derived Poliovirus Identified by Environmental Surveillance and Immunization Response — Horn of Africa, 2017–2018

Update on Vaccine-Derived Poliovirus Outbreaks — Democratic Republic of the Congo and Horn of Africa, 2017–2018

“…However, in underimmunized populations, extensive person-to-person transmission of Sabin poliovirus can result in genetic reversion to neurovirulence and paralytic vaccine-derived poliovirus (VDPV) disease ( 1 ). This report updates (as of February 26, 2019) previous reports on circulating VDPV type 2 (cVDPV2) outbreaks during 2017–2018 in the Democratic Republic of the Congo (DRC) and in Somalia, which experienced a concurrent cVDPV type 3 (cVDPV3) outbreak * ( 2 , 3 ). In DRC, 42 cases have been reported in four cVDPV2 outbreaks; paralysis onset in the most recent case was October 7, 2018 ( 2 ).…”

Detection and characterization of polioviruses originating from urban sewage in Yaounde and Douala, Cameroon 2016–2017

“…However, prolonged transmission of undetected WPV type 1 was recently reported in the Borno State of Nigeria [25]. Since 2016, type 2 circulating VDPV associated outbreaks have also been recently documented in multiple locations including Democratic Republic of Congo, Nigeria, Somalia, Pakistan and Syria; likely as result of the reduction of the population immunity against the PV type 2 [5, 24, 26, 27]. Despite the absence of WPVs and circulating VDPVs in Cameroon since 2014, it remains essential to maintain high quality AFP surveillance supplemented by extended environmental surveillance in order to ensure rapid detection and control of VDPV emergence and WPV importations in polio-free countries.…”

Update on Vaccine-Derived Polioviruses — Worldwide, January 2017–June 2018

“…No additional cases were reported from the cVDPV2 outbreaks first reported in Nigeria and Pakistan in 2016. New outbreaks were reported in DRC (three cVDPV2 emergences); Somalia (one cVDPV2 emergence and one cVDPV3 emergence) with linked cVPDV2 isolation in sewage in Kenya ( 7 ); Nigeria (two cVDPV2 emergences); and Papua New Guinea (one cVDPV1 emergence) (Table). During the reporting period, 113 cVDPV2 cases were detected (Table), including 74 in Syria, 33 in DRC, four in Nigeria, and two in Somalia.…”