title: Design and baseline data of a randomized trial to evaluate coverage and frequency of mass treatment with azithromycin: the Partnership for Rapid Elimination of Trachoma (PRET) in Tanzania and The Gambia.
abstract: OBJECTIVE
  Trachoma is the principal cause of infectious blindness. As part of its strategy to eliminate trachoma, the World Health Organization recommends annual mass antibiotic treatment for at least 3 years with an 80% population coverage target. However, to date, ideal population coverage and mass treatment duration have not been determined and further evaluation of treatment recommendations in areas of varying endemicity is warranted. The studies presented here evaluate the impact of coverage level and frequency of mass treatment with single dose azithromycin on trachoma and ocular C. trachomatis infection.
  
  
  METHODS
  The Partnership for the Rapid Elimination of Trachoma supervises 2 randomized, community-based clinical trials in Tanzania and The Gambia. Although each trial is a stand-alone effort, protocols, data collection, and analytic approaches have been harmonized to permit generalizations. Communities in each site were randomized using a 2X2 factorial design to standard (80%-90.0%) versus high (over 90.0%) treatment coverage; communities were further randomized to annual treatment for 3 years versus a "graduation" rule where evidence indicates an absence of follicular trachoma or infection and annual treatment is halted.
  
  
  RESULTS
  Average prevalence of follicular trachoma in children age less than 5 years was 32.2% in Tanzania and 5.96% in The Gambia. Randomization appeared to be effective, as prevalence was not statistically different between the arms within each country.
  
  
  CONCLUSIONS
  There are challenges in harmonizing 2, large trials in Africa. Study outcomes will provide critical data to national trachoma control programs on treatment methodology and resource allocation toward elimination of the disease.
authors.affiliation: Dana Center for Preventive Ophthalmology, Johns Hopkins University, Baltimore, MD, USA. dstare1@jhmi.edu
authors.forename: Dianne
authors.initials: D
authors.lastname: Stare
authors.forename: Emma
authors.initials: E
authors.lastname: Harding-Esch
authors.forename: Beatriz
authors.initials: B
authors.lastname: Munoz
authors.forename: Robin
authors.initials: R
authors.lastname: Bailey
authors.forename: David
authors.initials: D
authors.lastname: Mabey
authors.forename: Martin
authors.initials: M
authors.lastname: Holland
authors.forename: Charlotte
authors.initials: C
authors.lastname: Gaydos
authors.forename: Sheila
authors.initials: S
authors.lastname: West
mesh_terms: D000900:Anti-Bacterial Agents / Q000008:administration & dosage*; D017963:Azithromycin / Q000008:administration & dosage*; D002675:Child, Preschool; D002690:Chlamydia Infections / Q000188:drug therapy / Q000453:epidemiology; D005260:Female; D005714:Gambia / Q000453:epidemiology; D006801:Humans; D008297:Male; D015995:Prevalence; D011785:Quality Assurance, Health Care; D012107:Research Design; D016037:Single-Blind Method; D013636:Tanzania / Q000453:epidemiology; D014141:Trachoma / Q000188:drug therapy* / Q000453:epidemiology*
chemical_list: D000900:Anti-Bacterial Agents; D017963:Azithromycin