title: Poliovirus immunity among pregnant females aged 15-44 years, Namibia, 2010.
abstract: BACKGROUND
  Poliovirus (PV) antibody seroprevalence studies assess population immunity, verify an immunization program's performance and vaccine efficacy, and guide polio eradication strategy. Namibia experienced a polio outbreak among adults in 2006, yet population seroimmunity was unknown.
  
  
  METHODS
  We tested 2061 specimens from Namibian pregnant females aged 15-44 years for neutralizing antibody to PV types 1-3 (PV1-3); all females were sampled during the 2010 National HIV Sentinel Survey. We determined the proportion of females seropositive for PV antibody by 5-year age strata, and analyzed factors associated with seropositivity, including age, gravidity, human immunodeficiency virus (HIV) infection status, residence, and antiretroviral treatment, by log-binomial regression.
  
  
  RESULTS
  The seroprevalence was 94.6% for PV1, 97.0% for PV2, and 85.1% for PV3. HIV-positive females had significantly lower seroprevalence than HIV-negative females for PV1 (91.8% vs 95.3%; P<.01) and PV3 (80.0% vs 86.1%; P<.01) but not for PV2 (96.4% vs 97.1%; P=.3). The prevalence ratio of seropositivity for HIV-positive females versus HIV-negative females was 0.95 (95% confidence interval [CI], .92-.98) for PV1, 0.99 (95% CI, .97-1.01) for PV2, and 0.92 (95% CI, .87-.96) for PV3.
  
  
  CONCLUSIONS
  Despite relatively high PV seroprevalence, Namibia might remain at risk for a PV outbreak, particularly in lower-seroprevalence populations, such as HIV-positive females. Namibia should continue to maintain high routine polio vaccination coverage.
authors.affiliation: Centers for Disease Control and Prevention, Global Immunization Division, United States.
authors.forename: Cristina V
authors.initials: CV
authors.lastname: Cardemil
authors.affiliation: Ministry of Health and Social Services, Namibia.
authors.forename: Anna
authors.initials: A
authors.lastname: Jonas
authors.affiliation: Centers for Disease Control and Prevention, Division of Global HIV/AIDS, Namibia.
authors.forename: Sue
authors.initials: S
authors.lastname: Gerber
authors.affiliation: Centers for Disease Control and Prevention, Division of Viral Diseases, United States.
authors.forename: William C
authors.initials: WC
authors.lastname: Weldon
authors.affiliation: Centers for Disease Control and Prevention, Division of Viral Diseases, United States.
authors.forename: M Steven
authors.initials: MS
authors.lastname: Oberste
authors.affiliation: Centers for Disease Control and Prevention, Division of Global HIV/AIDS, Namibia.
authors.forename: Anita
authors.initials: A
authors.lastname: Beukes
authors.affiliation: Centers for Disease Control and Prevention, Division of Global HIV/AIDS, Namibia.
authors.forename: Souleymane
authors.initials: S
authors.lastname: Sawadogo
authors.affiliation: Centers for Disease Control and Prevention, Division of Global HIV/AIDS, Namibia.
authors.forename: Sadhna V
authors.initials: SV
authors.lastname: Patel
authors.affiliation: Ministry of Health and Social Services, Namibia.
authors.forename: Sikota
authors.initials: S
authors.lastname: Zeko
authors.affiliation: Ministry of Health and Social Services, Namibia.
authors.forename: Clementine
authors.initials: C
authors.lastname: Muroua
authors.affiliation: Namibia Institute of Pathology.
authors.forename: Esegiel
authors.initials: E
authors.lastname: Gaeb
authors.affiliation: Centers for Disease Control and Prevention, Global Immunization Division, United States.
authors.forename: Kathleen
authors.initials: K
authors.lastname: Wannemuehler
authors.affiliation: Centers for Disease Control and Prevention, Global Immunization Division, United States.
authors.forename: James L
authors.initials: JL
authors.lastname: Goodson
mesh_terms: D000293:Adolescent; D000328:Adult; D057134:Antibodies, Neutralizing / Q000097:blood; D000914:Antibodies, Viral / Q000097:blood*; D004196:Disease Outbreaks; D005260:Female; D006801:Humans; D009276:Namibia / Q000453:epidemiology; D011051:Poliomyelitis / Q000453:epidemiology* / Q000517:prevention & control*; D017955:Poliovirus / Q000276:immunology*; D023321:Poliovirus Vaccines / Q000008:administration & dosage / Q000276:immunology; D011247:Pregnancy; D016036:Seroepidemiologic Studies; D014611:Vaccination / Q000706:statistics & numerical data; D055815:Young Adult
chemical_list: D057134:Antibodies, Neutralizing; D000914:Antibodies, Viral; D023321:Poliovirus Vaccines
keywords: HIV; Namibia; OPV; adults; neutralizing antibody; polio; poliovirus; population immunity; pregnant women; seroprevalence