Partnership for Rapid Elimination of Trachoma

A randomized, 2x2 factorial designed trial will be implemented in each of the three
countries. Communities will be randomized to two different coverage targets (80%-89% versus
≥90%) for three years of mass treatment.

In The Gambia and Tanzania, communities will be further randomized to yearly mass treatment
versus mass treatment at baseline followed by yearly mass treatment only if trachoma
prevalence in sentinel children is greater than 5%. The communities will continue to be
followed and treatment will resume if trachoma prevalence is found to be 20% or greater at
the 12 or 18 month surveys.

In Niger, communities will be randomized to the different coverage levels for annual mass
azithromycin distribution and further randomized to biannual treatment at the two coverage
targets for children ages twelve or younger.

Cross-sectional rates of trachoma and infection will be determined by examining sentinel
children, age five years or younger, randomly selected from each community based on a
community census. The census will be updated each year, and villages will be monitored at
baseline, 6, 12, 18, 24, 30, and 36 months for infection and clinical disease.

The three-year study is in accord with the WHO guidelines which recommend three years of
annual mass treatment followed by a re-survey to determine need for further treatment. We
will evaluate the efficacy of guiding further mass treatment according to a laboratory test
for Chlamydia or WHO guidelines. Where we estimate communities have infection rates less
than 5% in sentinel children, or TF rates less than 5%, the community will be "graduated"
from further mass treatment and followed for up to three years to look for evidence of
re-emergent infection and disease. If rates of infection are found to be 20% or more return
at the 12 or 18 month survey, mass treatment will be re-initiated.