GET 2020

Answers to research questions paramount for eliminating trachoma

Since its launch in 1997, GET 2020, the Alliance for Global Elimination of Trachoma by 2020, has made some encouraging progress towards achieving its goal. However, the programme's ultimate success may depend on finding answers on issues affecting the rapidity with which trachoma elimination can be achieved, said Sheila K West PhD, at the annual meeting of the Association for Research in Vision and Ophthalmology.

'There is some good news to report that indicates the multifaceted strategy of GET 2020 is working. For example, although trachoma is still the leading infectious cause of avoidable blindness and visual impairment in the world, it has fallen from second place on the list of overall causes of blindness in 1997 to fifth in 2010. In addition, many countries are now poised to apply for certification of elimination of trachoma and that list is growing,' said Dr West, El-Maghraby professor of preventive ophthalmology, Wilmer Eye Institute, Johns Hopkins University, Baltimore, MD.

GET 2020 defines elimination of trachoma as prevalence below five per cent for follicular trachoma in children less than 10 years old and below one per 1,000 population for trichiasis. The effort to achieve these objectives involves a four-pronged strategy aimed at controlling all phases of trachoma. Known by the acronym 'SAFE', the interventions involve Surgery for trichiasis in eyes in imminent danger of vision loss, mass treatment with Antibiotics to reduce the community pool of Chlamydia trachomatis infection, Face washing to reduce transmission from ocular and nasal secretions, and Environmental improvements to interrupt transmission and prevent re-emergence.

Surgery

The fact that the rate of trichiasis recurrence one year after surgery has been reported to be as high as 80 per cent speaks to the importance of training and certification of surgeons, but also to the need for research to identify ways for increasing surgical success.

'A clinical trial is ongoing comparing surgery using a new clamp versus the standard bilamellar tarsal rotation procedure. However, other creative ways must be thought of for modifying surgery to achieve better outcomes,' Dr West said.

There is also a need to know how long an active trichiasis surgical programme must be maintained to manage incident cases after active trachoma is eliminated. Available data suggests the answer is probably 10 years at least, but more definitive information is needed.

Antibiotics

Research is also needed to determine the trajectory of elimination of C. trachomatis so that when countries commit resources to mass antibiotic administration, they can be given accurate information about how long it will take to reach programme goals. While it was originally recommended that mass treatment with a single annual dose of azithromycin should continue for three years, a five-year programme is now being advocated for highly endemic areas, and other information suggests 10 years may be needed if coverage is not consistent or high.

'We only have nine years left before 2020. It is possible we can shorten the time needed for mass treatment by treating more aggressively, perhaps treating children every six months, but research is needed to validate that approach,' said Dr West.

It remains to be determined whether infection will re-emerge once antibiotic pressure stops, and what are the risk factors for its return. Experience so far shows that infection can re-emerge fairly quickly if mass antibiotic treatment stops too soon. However, even in Ethiopia, where children were treated aggressively and the infection rate declined to two per cent, the infection returned after antibiotic pressure ceased, Dr West noted.

Research to identify better indicators of infection than simply signs of clinical trachoma is also needed considering there is a decoupling between clinical signs and infection status once mass antibiotic treatment begins.

Face washing and environmental strategies provide the foundation for sustained elimination of trachoma. However, recognition of low uptake of hygienic measures in some areas speaks to the need for ethnographic research to identify barriers to community participation and trials evaluating the efficacy of methods for overcoming the impediments. GET 2020 could also benefit from research identifying ways to integrate the elements of SAFE with existing disease control programmes, such as for malaria and neglected tropical diseases.