title: Factors contributing to outbreaks of wild poliovirus type 1 infection involving persons aged ≥15 years in the Democratic Republic of the Congo, 2010-2011, informed by a pre-outbreak poliovirus immunity assessment.
abstract: BACKGROUND
  The Democratic Republic of the Congo (DRC) experienced atypical outbreaks of wild poliovirus type 1 (WPV1) infection during 2010-2011 in that they affected persons aged ≥15 years in 4 (Bandundu, Bas Congo, Kasaï Occidental, and Kinshasa provinces) of the 6 provinces with outbreaks.
  
  
  METHODS
  Analyses of cases of WPV1 infection with onset during 2010-2011 by province, age, polio vaccination status, and sex were conducted. The prevalence of antibodies to poliovirus (PV) types 1, 2, and 3 was assessed in sera collected before the outbreaks from women attending antenatal clinics in 3 of the 4 above-mentioned provinces.
  
  
  RESULTS
  Of 193 cases of WPV1 infection during 2010-2011, 32 (17%) occurred in individuals aged ≥15 years. Of these 32 cases, 31 (97%) occurred in individuals aged 16-29 years; 9 (28%) were notified in Bandundu, 17 (53%) were notified in Kinshasa, and 22 (69%) had an unknown polio vaccination status. In the seroprevalence assessment, PV type 1 and 3 seroprevalence was lower among women aged 15-29 years in Bandundu and Kinshasa, compared with those in Kasaï Occidental. Seropositivity to PVs was associated with increasing age, more pregnancies, and a younger age at first pregnancy.
  
  
  CONCLUSIONS
  This spatiotemporal analysis strongly suggests that the 2010-2011 outbreaks of WPV1 infection affecting young adults were caused by a PV type 1 immunity gap in Kinshasa and Bandundu due to insufficient exposure to PV type 1 through natural infection or vaccination. Poliovirus immunity gaps in this age group likely persist in DRC.
authors.affiliation: Global Immunization Division.
authors.forename: Mary M
authors.initials: MM
authors.lastname: Alleman
authors.affiliation: Global Immunization Division.
authors.forename: Kathleen A
authors.initials: KA
authors.lastname: Wannemuehler
authors.affiliation: Division of Viral Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia.
authors.forename: William C
authors.initials: WC
authors.lastname: Weldon
authors.affiliation: Programme National de Lutte contre les IST/SIDA.
authors.forename: Jean Pierre
authors.initials: JP
authors.lastname: Kabuayi
authors.affiliation: Programme National de Lutte contre les IST/SIDA.
authors.forename: Felly
authors.initials: F
authors.lastname: Ekofo
authors.affiliation: Programme National de Lutte contre les IST/SIDA.
authors.forename: Samuel
authors.initials: S
authors.lastname: Edidi
authors.affiliation: Expanded Programme on Immunization, Ministry of Public Health.
authors.forename: Audry
authors.initials: A
authors.lastname: Mulumba
authors.affiliation: Immunization, Vaccines, and Emergencies Cluster, World Health Organization.
authors.forename: Albert
authors.initials: A
authors.lastname: Mbule
authors.affiliation: Immunization, Vaccines, and Emergencies Cluster, World Health Organization.
authors.forename: Renée N
authors.initials: RN
authors.lastname: Ntumbannji
authors.affiliation: Immunization, Vaccines, and Emergencies Cluster, World Health Organization.
authors.forename: Tiekoura
authors.initials: T
authors.lastname: Coulibaly
authors.affiliation: Division of Global HIV/AIDS, Centers for Disease Control and Prevention, Kinshasa, Democratic Republic of the Congo.
authors.forename: Nadine
authors.initials: N
authors.lastname: Abiola
authors.affiliation: Division of Global HIV/AIDS, Centers for Disease Control and Prevention, Kinshasa, Democratic Republic of the Congo.
authors.forename: Minlangu
authors.initials: M
authors.lastname: Mpingulu
authors.affiliation: Division of Global HIV/AIDS, Centers for Disease Control and Prevention, Kinshasa, Democratic Republic of the Congo.
authors.forename: Kassim
authors.initials: K
authors.lastname: Sidibe
authors.affiliation: Division of Viral Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia.
authors.forename: M Steven
authors.initials: MS
authors.lastname: Oberste
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000914:Antibodies, Viral / Q000097:blood*; D015023:Democratic Republic of the Congo / Q000453:epidemiology; D060740:Disease Eradication; D004196:Disease Outbreaks; D005260:Female; D006801:Humans; D008875:Middle Aged; D011051:Poliomyelitis / Q000453:epidemiology* / Q000276:immunology* / Q000517:prevention & control / Q000821:virology; D017955:Poliovirus / Q000276:immunology* / Q000302:isolation & purification*; D011247:Pregnancy; D019371:Topography, Medical; D055815:Young Adult
chemical_list: D000914:Antibodies, Viral
keywords: Africa; Democratic Republic of the Congo; neutralizing antibodies; polio eradication; polio in adults; polio seroprevalence; wild poliovirus outbreaks