title: [Pertussis outbreak in a poorly immunized community].
abstract: BACKGROUND
  The aim of this study was to describe the clinical, serological and epidemiological findings of a pertussis outbreak in an insufficiently vaccinated gipsy community.
  
  
  METHODS
  Ten cases (catarrhal illness with cough of 2 weeks duration) were identified through an active search. In four of them, two paired serum samples were obtained and total IgG against Bordetella pertussis and IgG and IgA against pertussis toxin (PT) and filamentous hemagglutinin (FHA) were determined. The diagnostic criteria was seroconversion. A comparative analysis between cases and healthy children younger than 15 years (gipsy community) was carried out and we estimated, by means of a logistical regression analysis, the odds ratio (OR) of several factors.
  
  
  RESULTS
  The highest attack rate (50%) was found in the 5 to 9 year-old group; 30% cases had not been vaccinated while 50% had been incorrectly vaccinated. No significant differences for age, gender or the vaccine status were detected. Three cases showed seroconversion for total IgG and two for IgG-PT and IgA-PT. Other possible pathogens were ruled out by serology.
  
  
  CONCLUSIONS
  Despite the high vaccine coverage against pertussis in paediatric age in Spain, some susceptible population groups remain, mainly due to an incorrect vaccination. Our serological results firmly support the suspicion of B. pertussis as the etiologic agent of the outbreak.
authors.affiliation: Servicio de Salud Pública del Area III. Consejería de Sanidad. Comunidad de Madrid. Alcalá de Henares. Madrid. Spain. javier.segura@madrid.org
authors.forename: Javier
authors.initials: J
authors.lastname: Segura del Pozo
authors.forename: Juan Carlos
authors.initials: JC
authors.lastname: Sanz Moreno
authors.forename: María Jesús
authors.initials: MJ
authors.lastname: Gascón Sancho
authors.forename: Esther
authors.initials: E
authors.lastname: Ramos Lledó
authors.forename: Fernando
authors.initials: F
authors.lastname: de Ory Manchón
authors.forename: Marisa
authors.initials: M
authors.lastname: Fernández Díaz
mesh_terms: D000907:Antibodies, Bacterial / Q000097:blood; D001886:Bordetella pertussis / Q000276:immunology / Q000302:isolation & purification*; D002648:Child; D002675:Child, Preschool; D004196:Disease Outbreaks; D005260:Female; D006801:Humans; D007070:Immunoglobulin A / Q000032:analysis; D007074:Immunoglobulin G / Q000032:analysis; D007223:Infant; D008297:Male; D012307:Risk Factors; D006178:Romani People; D012698:Serologic Tests; D013030:Spain / Q000453:epidemiology; D014611:Vaccination; D014917:Whooping Cough / Q000453:epidemiology* / Q000276:immunology
chemical_list: D000907:Antibodies, Bacterial; D007070:Immunoglobulin A; D007074:Immunoglobulin G