Neglected tropical diseases

WHO leads multi-country study to simplify oral treatment of yaws

Lead researcher appeals for free availability of medicine to accelerate eradication of the disease


29 July 2016 | Geneva −− The World Health Organization (WHO) is leading a study in two countries affected by yaws to determine whether a lower dose of azithromycin (a long-acting antibiotic) is as effective as the current dose in curing the disease. The WHO roadmap on neglected tropical diseases targets the eradication of yaws by 2020.

Scenes from yaws clinical trial in Papua New Guinea (Neglected Tropical Diseases Programme, Department of Health)

The current WHO-recommended dose of oral azithromycin (30 mg/kg; maximum 2 g) is used also to treat trachoma but at a lower dose (20 mg/kg; maximum 1 g).

“If the efficacy of a lower dose is established, it will be a great step forward in harmonizing and delivering treatment to simultaneously tackle the two poverty-related diseases wherever they occur” said Dr Kingsley Asiedu, Medical Officer in charge of WHO’s yaws eradication programme. “This would also mean less azithromycin needed to achieve the eradication of yaws.”

Yaws is a chronic skin disease that mainly affects children. Without treatment, infection can lead to chronic disfigurement and disability. The study, involving a number of national and international collaborators, is expected to recruit 600 serologically positive children with yaws in two countries – Ghana and Papua New Guinea.

In Ghana, recruitment started in June 2015 and nearly 400 participants have been enrolled. The 6-month follow-up of all the participants has just been completed. In Papua New Guinea the study started in May 2016 involving 200 participants and is expected to run until the end of 2016.

The study is funded by the Neglected Tropical Diseases Support Center of the Task Force for Global Health (Decatur, GA, USA) with technical support from the London School of Hygiene and Tropical Medicine (London, UK) and the Barcelona Institute for Global Health, or ISGlobal (Barcelona Spain). The United States Centers for Disease Control and Prevention provides laboratory support. The final results will be available at the beginning of 2017.

Discovery

Until 2012, the standard treatment for yaws was a single injection of benzathine penicillin. However, research conducted by Dr Oriol Mitjà and his colleagues in Papua New Guinea and published that year found that a single dose of oral azithromycin is as effective as benzathine penicillin injection.

This discovery is of great significance as it makes large-scale treatment of affected populations more practical. More importantly, it obviates the cumbersome logistics and the need for injections, which require administration by trained health-care workers.

Based on the use of oral azithromycin, WHO published the Morges Strategy in 2012 - a shift from the use of benzathine penicillin injection for more than 60 years.

Documentary

In recognition of Dr Mitjà’s pioneering work, the United Nations Department of Public Information organized the screening of a documentary that captures the ease with which oral azithromycin is administered to children and its benefits to affected populations in Papua New Guinea and the world.

During a panel discussion following the screening at the United Nations headquarters (New York, NY, 12 July 2016), Dr Mitjà appealed to governments, philanthropic organizations and pharmaceutical companies to make azithromycin tablets available free of charge to affected populations so that the world can finally triumph over yaws.

A tablet (500 mg) of azithromycin costs US$ 0.17 and most children need one or two to get cured.

Only 13 countries are known to be currently endemic for yaws, compared with 88 in the 1950s. Pilot implementation of the new eradication strategy in five countries (Congo, Ghana, Papua New Guinea, the Solomon Islands and Vanuatu) has provided promising results and practical lessons for scale-up.

Besides polio and dracunculiasis (guinea-worm disease), yaws is the third human disease targeted for eradication by WHO.

Ashok Moloo
WHO/HTM/NTD
Telephone: +41 22 791 1637
Mobile phone: +41 79 540 50 86
molooa@who.int