The study will be a single blinded, randomized, controlled open label non-inferiority phase III, trial with two parallel groups, conducted in Ghana and Papua New Guinea (PNG). The ultimate goal is to establish if a 20mg/kg dose of azithromycin is as effective as a 30mg/kg dose in the treatment of yaws. Approximately 600 clinically and serologically diagnosed yaws patients will be included in the study. Patients will be randomized to receive treatment with the two antibiotic regimens as follow: (i) Regimen I (AZT20): Single oral dose of 20 mg/kg azithromycin (ii) Regimen II (AZT30): Single oral dose of 30 mg/kg azithromycin. The follow-up period of patients will be 6 months. Assessments before, during and after the antibiotic treatment will include full medical history, clinical assessment of the lesion and, laboratory investigations. The primary efficacy parameters are healing of the lesion at 4 weeks and a four-fold decline in RPR titre at 6 months after start of treatment.

Inclusion Criteria:

• Aged 6 to 16 years
• Clinical lesion consistent with primary or secondary yaws -Primary ulcer or papilloma
• Dually-Positive Chembio DPP Syphilis Screen & Confirm
• Informed Consent and Assent (for children 12-16 years)

Exclusion Criteria:

1. Known allergy to azithromycin or macrolides.
2. Treatment with long-acting penicillin or alternative antibiotic with activity against T. pallidum within the last 3 months (ceftriaxone, azithromycin or doxycycline, amoxicillin).
3. Patients with current treatment with any drugs likely to interact with the study medication.
4. Patients who are unable to take oral medication or having gastrointestinal disease likely to interfere with drug absorption.
5. Patients who may not be able to comply with the requirements of the study protocol including follow up visits.
6. Patients who are not willing to give informed consent (patient and/or parent/legal representative), or who withdraw consent.