title: Population immunity to polioviruses among preschool children from four urban underserved low income communities, United States, 1997-2001.
abstract: BACKGROUND
  In 1997, the Advisory Committee for Immunization Practices (ACIP) recommended a change in polio vaccination policy, the first in 30 years, from the oral poliovirus vaccine (OPV) to a combined OPV/inactivated poliovirus vaccine (IPV) sequential schedule for routine childhood vaccination. To evaluate the impact of the change in polio vaccination schedule on population immunity, we conducted a seroprevalence survey among low income preschool children from selected urban areas.
  
  
  METHODS
  A repeat cross-sectional serosurvey was conducted during 1997-2001. Children 19-35 months of age receiving well-child care were recruited from outpatient clinics of academic medical centers. Serum samples were obtained and tested for neutralizing antibodies to polioviruses types 1, 2 and 3. A standardized questionnaire was administered to the parents or guardians of enrolled children.
  
  
  RESULTS
  Seroprevalence remained high and stable during the study period. Among children sampled in the last study year (initiating their vaccinations from August 1997 through September 2000), seroprevalence was >/=95% to poliovirus serotypes 1 and 2 and >/=94% to serotype 3. Overall coverage with >/=3 doses of polio vaccine was 82-95% across sites during this period. The proportion initiating their vaccination schedule with IPV increased from 2.6% in study year 1 (children born October 1994-January 1997) to 80% in study year 4 (children born October 1997-January 2000).
  
  
  CONCLUSIONS
  Children in these underserved low income communities are well-protected against the spread of polioviruses; the introduction of IPV did not adversely impact coverage or seroprevalence. Continued monitoring is needed to evaluate population immunity in the absence of OPV circulation.
authors.affiliation: National Immunization Program, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA. rprevots@niaid.nih.gov
authors.forename: D Rebecca
authors.initials: DR
authors.lastname: Prevots
authors.forename: F Brian
authors.initials: FB
authors.lastname: Pascual
authors.forename: Mary Lu
authors.initials: ML
authors.lastname: Angellili
authors.forename: Robert
authors.initials: R
authors.lastname: Brayden
authors.forename: Matilde
authors.initials: M
authors.lastname: Irigoyen
authors.forename: Philip
authors.initials: P
authors.lastname: Larussa
authors.forename: Mark
authors.initials: M
authors.lastname: Sawyer
authors.forename: Andrew L
authors.initials: AL
authors.lastname: Baughman
authors.forename: Mark A
authors.initials: MA
authors.lastname: Pallansch
mesh_terms: D000914:Antibodies, Viral / Q000097:blood*; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D006801:Humans; D007223:Infant; D011051:Poliomyelitis / Q000517:prevention & control; D017955:Poliovirus / Q000276:immunology*; D023321:Poliovirus Vaccines / Q000276:immunology; D016036:Seroepidemiologic Studies; D013997:Time Factors; D014481:United States; D014611:Vaccination
chemical_list: D000914:Antibodies, Viral; D023321:Poliovirus Vaccines