title: Survey of poliovirus antibodies in Kano, Northern Nigeria.
abstract: BACKGROUND
  In 1988, the World Health Assembly resolved to eradicate poliomyelitis. Since then, much progress towards this goal has been made, but three countries including Nigeria remain polio-endemic as of end 2012. To assess the immunity level against poliomyelitis in young children in Northern Nigeria, we conducted a seroprevalence survey in the Kano Metropolitan Area (KMA) in May 2011.
  
  
  METHODS
  Parents or guardians of infants aged 6-9months or children aged 36-47months presenting to the outpatient department of Murtala Mohammad Specialist Hospital were approached for participation, screened for eligibility and were asked to provide informed consent. After that, a questionnaire was administered and blood was collected for neutralization assay.
  
  
  RESULTS
  A total of 327 subjects were enrolled. Of these, 313 (96%) met the study requirements and were analyzed (161 [51%] aged 6-9months and 152 [49%] aged 36-47months). Among subjects aged 6-9months, seroprevalence was 81% (95% confidence interval [CI] 75-87%) to poliovirus type 1, 76% (95% CI 68-81%) to poliovirus type 2, and 73% (95% CI 67-80%) to poliovirus type 3. Among subjects aged 36-47months, the seroprevalence was 91% (95% CI 86-95%) to poliovirus type 1, 87% (95% CI 82-92%) for poliovirus type 2, and 86% (95% CI 80-91%) to poliovirus type 3. Seroprevalence was associated with history of oral poliovirus vaccine (OPV) doses, maternal education and gender.
  
  
  CONCLUSIONS
  Seroprevalence is lower than required levels for poliovirus interruption in the KMA. Persistence of immunity gaps in the 36-47months group is a big concern. Since higher number of vaccine doses is associated with higher seroprevalence, it implies that failure-to-vaccinate and not vaccine failure accounts for the suboptimal seroprevalence. Intensified efforts are necessary to administer polio vaccines to all target children and surpass the threshold levels for herd immunity.
authors.affiliation: Department of Community Medicine, Aminu Kano Teaching Hospital & Bayero University, Kano, Nigeria.
authors.forename: Zubairu
authors.initials: Z
authors.lastname: Iliyasu
authors.affiliation: National Primary Health Care Development Agency, Abuja, Nigeria.
authors.forename: Eric
authors.initials: E
authors.lastname: Nwaze
authors.affiliation: World Health Organization, Geneva, Switzerland.
authors.forename: Harish
authors.initials: H
authors.lastname: Verma
authors.affiliation: Department of Pediatrics, Aminu Kano Teaching Hospital & Bayero University, Kano, Nigeria.
authors.forename: Asani O
authors.initials: AO
authors.lastname: Mustapha
authors.affiliation: World Health Organization, Abuja, Nigeria.
authors.forename: Goitom
authors.initials: G
authors.lastname: Weldegebriel
authors.affiliation: World Health Organization, Abuja, Nigeria.
authors.forename: Alex
authors.initials: A
authors.lastname: Gasasira
authors.affiliation: Centers for Disease Control and Prevention, Atlanta, GA, United States.
authors.forename: Kathleen A
authors.initials: KA
authors.lastname: Wannemuehler
authors.affiliation: Centers for Disease Control and Prevention, Atlanta, GA, United States.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Pallansch
authors.affiliation: Department of Community Medicine, Aminu Kano Teaching Hospital & Bayero University, Kano, Nigeria.
authors.forename: Auwalu U
authors.initials: AU
authors.lastname: Gajida
authors.affiliation: National Primary Health Care Development Agency, Abuja, Nigeria; Duke Global Health Institute, Duke University, Durham, USA.
authors.forename: Muhammad
authors.initials: M
authors.lastname: Pate
authors.affiliation: World Health Organization, Geneva, Switzerland. Electronic address: sutterr@who.int.
authors.forename: Roland W
authors.initials: RW
authors.lastname: Sutter
mesh_terms: D000914:Antibodies, Viral / Q000097:blood*; D002675:Child, Preschool; D060740:Disease Eradication; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D009549:Nigeria / Q000453:epidemiology; D011051:Poliomyelitis / Q000453:epidemiology* / Q000517:prevention & control; D017955:Poliovirus / Q000145:classification; D011055:Poliovirus Vaccine, Oral / Q000627:therapeutic use; D012307:Risk Factors; D016036:Seroepidemiologic Studies
chemical_list: D000914:Antibodies, Viral; D011055:Poliovirus Vaccine, Oral
keywords: Kano; Nigeria; Oral poliovirus vaccine; Poliomyelitis; Seroprevalence