title: Outbreak of type 2 vaccine-derived poliovirus in Nigeria: emergence and widespread circulation in an underimmunized population.
abstract: Wild poliovirus has remained endemic in northern Nigeria because of low coverage achieved in the routine immunization program and in supplementary immunization activities (SIAs). An outbreak of infection involving 315 cases of type 2 circulating vaccine-derived poliovirus (cVDPV2; >1% divergent from Sabin 2) occurred during July 2005-June 2010, a period when 23 of 34 SIAs used monovalent or bivalent oral poliovirus vaccine (OPV) lacking Sabin 2. In addition, 21 "pre-VDPV2" (0.5%-1.0% divergent) cases occurred during this period. Both cVDPV and pre-VDPV cases were clinically indistinguishable from cases due to wild poliovirus. The monthly incidence of cases increased sharply in early 2009, as more children aged without trivalent OPV SIAs. Cumulative state incidence of pre-VDPV2/cVDPV2 was correlated with low childhood immunization against poliovirus type 2 assessed by various means. Strengthened routine immunization programs in countries with suboptimal coverage and balanced use of OPV formulations in SIAs are necessary to minimize risks of VDPV emergence and circulation.
authors.affiliation: Centers for Disease Control and Prevention, Atlanta, Georgia, USA. sgw1@cdc.gov
authors.forename: Steven
authors.initials: S
authors.lastname: Wassilak
authors.forename: Muhammad Ali
authors.initials: MA
authors.lastname: Pate
authors.forename: Kathleen
authors.initials: K
authors.lastname: Wannemuehler
authors.forename: Julie
authors.initials: J
authors.lastname: Jenks
authors.forename: Cara
authors.initials: C
authors.lastname: Burns
authors.forename: Paul
authors.initials: P
authors.lastname: Chenoweth
authors.forename: Emmanuel Ade
authors.initials: EA
authors.lastname: Abanida
authors.forename: Festus
authors.initials: F
authors.lastname: Adu
authors.forename: Marycelin
authors.initials: M
authors.lastname: Baba
authors.forename: Alex
authors.initials: A
authors.lastname: Gasasira
authors.forename: Jane
authors.initials: J
authors.lastname: Iber
authors.forename: Pascal
authors.initials: P
authors.lastname: Mkanda
authors.forename: A J
authors.initials: AJ
authors.lastname: Williams
authors.forename: Jing
authors.initials: J
authors.lastname: Shaw
authors.forename: Mark
authors.initials: M
authors.lastname: Pallansch
authors.forename: Olen
authors.initials: O
authors.lastname: Kew
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D004196:Disease Outbreaks; D005260:Female; D016679:Genome, Viral; D006291:Health Policy; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D009154:Mutation; D009549:Nigeria / Q000453:epidemiology; D011051:Poliomyelitis / Q000453:epidemiology* / Q000473:pathology / Q000821:virology*; D017955:Poliovirus / Q000235:genetics / Q000302:isolation & purification* / Q000472:pathogenicity*; D023321:Poliovirus Vaccines / Q000008:administration & dosage / Q000009:adverse effects*; D014611:Vaccination / Q000706:statistics & numerical data; D055815:Young Adult
chemical_list: D023321:Poliovirus Vaccines