title: Lessons and implications from a mass immunization campaign in squatter settlements of Karachi, Pakistan: an experience from a cluster-randomized double-blinded vaccine trial [NCT00125047].
abstract: OBJECTIVE
  To determine the safety and logistic feasibility of a mass immunization strategy outside the local immunization program in the pediatric population of urban squatter settlements in Karachi, Pakistan.
  
  
  METHODS
  A cluster-randomized double blind preventive trial was launched in August 2003 in 60 geographic clusters covering 21,059 children ages 2 to 16 years. After consent was obtained from parents or guardians, eligible children were immunized parenterally at vaccination posts in each cluster with Vi polysaccharide or hepatitis A vaccine. Safety, logistics, and standards were monitored and documented.
  
  
  RESULTS
  The vaccine coverage of the population was 74% and was higher in those under age 10 years. No life-threatening serious adverse events were reported. Adverse events occurred in less than 1% of all vaccine recipients and the main reactions reported were fever and local pain. The proportion of adverse events in Vi polysaccharide and hepatitis A recipients will not be known until the end of the trial when the code is broken. Throughout the vaccination campaign safe injection practices were maintained and the cold chain was not interrupted. Mass vaccination in slums had good acceptance. Because populations in such areas are highly mobile, settlement conditions could affect coverage. Systemic reactions were uncommon and local reactions were mild and transient. Close community involvement was pivotal for information dissemination and immunization coverage.
  
  
  CONCLUSIONS
  This vaccine strategy described together with other information that will soon be available in the area (cost/effectiveness, vaccine delivery costs, etc) will make typhoid fever control become a reality in the near future.
authors.affiliation: Department of Pediatrics, Aga Khan University, Karachi, Pakistan. mohammad.imran@aku.edu
authors.forename: Mohammad Imran
authors.initials: MI
authors.lastname: Khan
authors.forename: Rion Leon
authors.initials: RL
authors.lastname: Ochiai
authors.forename: Hasan Bin
authors.initials: HB
authors.lastname: Hamza
authors.forename: Shah Muhammad
authors.initials: SM
authors.lastname: Sahito
authors.forename: Muhammad Atif
authors.initials: MA
authors.lastname: Habib
authors.forename: Sajid Bashir
authors.initials: SB
authors.lastname: Soofi
authors.forename: Naveed Sarwar
authors.initials: NS
authors.lastname: Bhutto
authors.forename: Shahid
authors.initials: S
authors.lastname: Rasool
authors.forename: Mahesh K
authors.initials: MK
authors.lastname: Puri
authors.forename: Mohammad
authors.initials: M
authors.lastname: Ali
authors.forename: Shafi Mohammad
authors.initials: SM
authors.lastname: Wasan
authors.forename: Mohammad Jawed
authors.initials: MJ
authors.lastname: Khan
authors.forename: Remon
authors.initials: R
authors.lastname: Abu-Elyazeed
authors.forename: Bernard
authors.initials: B
authors.lastname: Ivanoff
authors.forename: Claudia M
authors.initials: CM
authors.lastname: Galindo
authors.forename: Tikki
authors.initials: T
authors.lastname: Pang
authors.forename: Allan
authors.initials: A
authors.lastname: Donner
authors.forename: Lorenz
authors.initials: L
authors.lastname: von Seidlein
authors.forename: Camilo J
authors.initials: CJ
authors.lastname: Acosta
authors.forename: John D
authors.initials: JD
authors.lastname: Clemens
authors.forename: Shaikh Qamaruddin
authors.initials: SQ
authors.lastname: Nizami
authors.forename: Zulfiqar A
authors.initials: ZA
authors.lastname: Bhutta