title: Costs of testing for ocular Chlamydia trachomatis infection compared to mass drug administration for trachoma in the Gambia: application of results from the PRET study.
abstract: BACKGROUND
  Mass drug administration (MDA) treatment of active trachoma with antibiotic is recommended to be initiated in any district where the prevalence of trachoma inflammation, follicular (TF) is ≥ 10% in children aged 1-9 years, and then to continue for at least three annual rounds before resurvey. In The Gambia the PRET study found that discontinuing MDA based on testing a sample of children for ocular Chlamydia trachomatis(Ct) infection after one MDA round had similar effects to continuing MDA for three rounds. Moreover, one round of MDA reduced disease below the 5% TF threshold. We compared the costs of examining a sample of children for TF, and of testing them for Ct, with those of MDA rounds.
  
  
  METHODS
  The implementation unit in PRET The Gambia was a census enumeration area (EA) of 600-800 people. Personnel, fuel, equipment, consumables, data entry and supervision costs were collected for census and treatment of a sample of EAs and for the examination, sampling and testing for Ct infection of 100 individuals within them. Programme costs and resource savings from testing and treatment strategies were inferred for the 102 EAs in the study area, and compared.
  
  
  RESULTS
  Census costs were $103.24 per EA plus initial costs of $108.79. MDA with donated azithromycin cost $227.23 per EA. The mean cost of examining and testing 100 children was $796.90 per EA, with Ct testing kits costing $4.80 per result. A strategy of testing each EA for infection is more expensive than two annual rounds of MDA unless the kit cost is less than $1.38 per result. However stopping or deciding not to initiate treatment in the study area based on testing a sample of EAs for Ct infection (or examining children in a sample of EAs) creates savings relative to further unnecessary treatments.
  
  
  CONCLUSIONS
  Resources may be saved by using tests for chlamydial infection or clinical examination to determine that initial or subsequent rounds of MDA for trachoma are unnecessary.
authors.affiliation: London School of Hygiene and Tropical Medicine, London, United Kingdom; Public Health England, HIV/STI Department, London, United Kingdom.
authors.forename: Emma
authors.initials: E
authors.lastname: Harding-Esch
authors.affiliation: Department of Economics, City University, London, United Kingdom.
authors.forename: Mireia
authors.initials: M
authors.lastname: Jofre-Bonet
authors.affiliation: Abacus International, Bicester, Oxfordshire, United Kingdom.
authors.forename: Jaskiran K
authors.initials: JK
authors.lastname: Dhanjal
authors.affiliation: MRC Laboratories, Fajara, The Gambia.
authors.forename: Sarah
authors.initials: S
authors.lastname: Burr
authors.affiliation: London School of Hygiene and Tropical Medicine, London, United Kingdom.
authors.forename: Tansy
authors.initials: T
authors.lastname: Edwards
authors.affiliation: London School of Hygiene and Tropical Medicine, London, United Kingdom.
authors.forename: Martin
authors.initials: M
authors.lastname: Holland
authors.affiliation: National Eye Health Programme, Banjul, The Gambia.
authors.forename: Ansumana
authors.initials: A
authors.lastname: Sillah
authors.affiliation: Dana Center for Preventive Ophthalmology, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, United States of America.
authors.forename: Sheila
authors.initials: S
authors.lastname: West
authors.affiliation: The Francis I. Proctor Foundation, University of California, San Francisco, San Francisco, California, United States of America.
authors.forename: Tom
authors.initials: T
authors.lastname: Lietman
authors.affiliation: The Francis I. Proctor Foundation, University of California, San Francisco, San Francisco, California, United States of America.
authors.forename: Jeremy
authors.initials: J
authors.lastname: Keenan
authors.affiliation: London School of Hygiene and Tropical Medicine, London, United Kingdom.
authors.forename: David
authors.initials: D
authors.lastname: Mabey
authors.affiliation: London School of Hygiene and Tropical Medicine, London, United Kingdom.
authors.forename: Robin
authors.initials: R
authors.lastname: Bailey
mesh_terms: D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D017963:Azithromycin / Q000627:therapeutic use; D002648:Child; D002675:Child, Preschool; D002692:Chlamydia trachomatis / Q000302:isolation & purification*; D005260:Female; D005714:Gambia / Q000453:epidemiology; D006801:Humans; D008297:Male; D008403:Mass Screening / Q000191:economics; D008875:Middle Aged; D014141:Trachoma / Q000175:diagnosis* / Q000188:drug therapy* / Q000191:economics / Q000453:epidemiology
chemical_list: D000900:Anti-Bacterial Agents; D017963:Azithromycin