title: Trial participation and vaccine desirability for Vi polysaccharide typhoid fever vaccine in Hue City, Viet Nam.
abstract: OBJECTIVE
  To identify demand for Vi typhoid fever vaccine for school-age children; obstacles and enabling factors for vaccine delivery; and socio-behavioural factors associated with trial participation and possible predictors of future vaccine acceptance, in Hue City, Viet Nam.
  
  
  METHODS
  Pre- and post-trial surveys of randomly selected households with children aged 6-17 years. Simple multinomial logistic analyses for ratios of relative risks (RRR) and significance on trial participation by demographics and variables related to typhoid fever, vaccination, and pre-trial experiences with information and consents. Multiple logistic regressions to assess differences in participation based on child's characteristics.
  
  
  RESULTS
  As many as 62.6% of households let all school age children participate, 10.2% let some participate, and 26.8% let none of their children participate in the trial. Factors associated with all children participating included past use of healthcare facilities (RRR, 0.45; 95% CI, 0.24-0.83), knowledge of vaccines (RRR, 0.17; 95% CI, 0.03-0.86), and perceived causes of typhoid fever (RRR, 0.90; 95% CI, 0.81-0.99). Factors associated with some children participating included utilization of healthcare facilities (RRR, 0.08; 95% CI, 0.01-0.66) and perceived severity of typhoid fever (RRR, 0.64; 95% CI 0.46-0.88). Participation was associated with satisfaction regarding pre-vaccination information and consent procedures. Children and adolescents were active decision-makers. Only 14 of 461 (2.2%) respondents would not use the Vi vaccine in the future for their child(ren).
  
  
  CONCLUSIONS
  Inter-related factors contribute to participation in a clinical vaccine trial, which may differ from desire to participate in a public health campaign. Educational campaigns need to be targeted to children and adolescents, and consideration for assent procedures for minors. Obtaining informed consent may affect trial participation within a social and political system unaccustomed to these procedures.
authors.affiliation: Department of Pediatrics, School of Medicine, University of Maryland, Baltimore MD, USA. lkaljee@peds.umaryland.edu
authors.forename: Linda M
authors.initials: LM
authors.lastname: Kaljee
authors.forename: Van
authors.initials: V
authors.lastname: Pham
authors.forename: Nguyen Dinh
authors.initials: ND
authors.lastname: Son
authors.forename: Nguyen Thai
authors.initials: NT
authors.lastname: Hoa
authors.forename: Vu Dinh
authors.initials: VD
authors.lastname: Thiem
authors.forename: Do Gia
authors.initials: DG
authors.lastname: Canh
authors.forename: Le Thi Kim
authors.initials: le TK
authors.lastname: Thoa
authors.forename: Mohammad
authors.initials: M
authors.lastname: Ali
authors.forename: Rion Leon
authors.initials: RL
authors.lastname: Ochiai
authors.forename: M Carolina
authors.initials: MC
authors.lastname: Danovaro-Holliday
authors.forename: Camilo J
authors.initials: CJ
authors.lastname: Acosta
authors.forename: Bonita
authors.initials: B
authors.lastname: Stanton
authors.forename: John
authors.initials: J
authors.lastname: Clemens
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D003469:Culture; D005191:Family Characteristics; D005260:Female; D019538:Health Care Surveys / Q000379:methods; D007722:Health Knowledge, Attitudes, Practice; D006801:Humans; D007258:Informed Consent / Q000523:psychology; D008297:Male; D008875:Middle Aged; D010290:Parents; D010342:Patient Acceptance of Health Care / Q000523:psychology*; D010353:Patient Education as Topic / Q000592:standards; D010358:Patient Participation / Q000523:psychology; D017060:Patient Satisfaction; D011135:Polysaccharides, Bacterial / Q000627:therapeutic use*; D012044:Regression Analysis; D012720:Severity of Illness Index; D014435:Typhoid Fever / Q000453:epidemiology / Q000517:prevention & control* / Q000523:psychology; D014436:Typhoid-Paratyphoid Vaccines / Q000627:therapeutic use*; D014744:Vietnam / Q000453:epidemiology
chemical_list: D011135:Polysaccharides, Bacterial; D014436:Typhoid-Paratyphoid Vaccines; C057664:Vi polysaccharide vaccine, typhoid