Trachoma is a blinding disease caused by ocular strains of Chlamydia trachomatis. The Carter Center and Proctor Foundation have been jointly conducting trachoma research in the Amhara region of Ethiopia for the past 10 years, through a series of clinical trials. We have found that repeated mass administration of oral azithromycin can greatly reduce the prevalence of trachoma, but mass antibiotics have been unable thus far to eliminate infection.
The World Health Organization recommends not only antibiotics for control of trachoma, but an entire SAFE strategy (Surgery for in-turned eyelids, Antibiotics, Facial hygiene promotion, and Environmental improvements such as latrines and water points). The rationale for the SAFE strategy is based on many years of observational studies on trachoma. Cross-sectional studies have found that clinically active trachoma and ocular chlamydial infection are associated with several indicators of poor hygiene, including dirty faces, face-seeking flies, long distance to water supply, and lack of household latrine. There are few randomized trials testing the impact of WASH improvements on trachoma.
In the past, the WHO has recommended targeted antibiotic treatments to those individuals with active disease, so this could be an alternative treatment strategy that would limit antibiotic use in the community and perhaps be cost-saving. However, little research has assessed targeted treatments as a strategy for trachoma elimination following repeated mass azithromycin distributions.
Our long term goal is to eliminate trachoma even in the most hyperendemic communities. This cluster-randomized clinical trial will determine the role of a comprehensive package of sanitation measures for the elimination of trachoma. We will monitor clinical disease with photography, and monitor infection with a newer chlamydial polymerase chain reaction (PCR) test (Abbott m2000) that is more sensitive than earlier generation tests, and provides quantification. We will monitor other potential health benefits of a WASH intervention and test its overall cost effectiveness. We will also assess a competing strategy for minimizing antibiotic use: that of targeted azithromycin treatments to children testing positive for ocular chlamydia. We will model the long-term cost-effectiveness of these competing strategies for trachoma control after completion of several rounds of mass azithromycin distributions.
Our monitoring has revealed a high uptake of the SWIFT I/WUHA I intervention as well as evidence of subsequent hygiene behavior changes. However, communities started out with a high burden of ocular chlamydia and preliminary data suggests that elimination will be unlikely. We therefore were granted an continuation grant (SWIFT II) to determine the long-term benefit of WASH for trachoma when combined with antibiotics, and second, to explore possibilities for low-cost, highly accurate point-of-care test for chlamydia.
With SWIFT II, we are extending the WUHA I trial by performing a single mass azithromycin distribution in all 40 communities after the final study visit (i.e., month 36), and continuing the WASH intervention in the 20 communities originally randomized to WASH. We are monitoring for ocular chlamydia via PCR of conjunctival swabs. We ask whether antibiotic distributions combined with a comprehensive, well-functioning WASH package is more likely to eliminate trachoma than antibiotics alone. We will also collect extra swabs and dried blood spots during routine monitoring visits and compare several inexpensive, commercially available NAATs and serologic tests for chlamydia. The SWIFT II trial leverages our existing SWIFT I research infrastructure and takes advantage of the fact that the intervention has already been implemented, and will have been operating for more than six years by the end of the proposed study. WASH interventions are thought to take a long time to work given their reliance on changing behavior, and thus we will increase the chances of finding an effect if one truly exists. Moreover, we will advance knowledge regarding trachoma surveillance, which has become increasingly important as the world moves towards global elimination. The results of the SWIFT II study will be of interest to the trachoma community, and regardless of the outcome will directly help trachoma programs decide how to spend their limited resources.
