Abstract:
To eliminate blinding trachoma, the World Health Organization emphasizes implementing the SAFE strategy,
which includes annual mass drug administration (MDA) with azithromycin to the whole population of endemic districts.
Prevalence surveys to assess impact at the district level are recommended after at least 3 years of intervention. The decision
to stop MDA is based on a prevalence of trachomatous inflammation follicular (TF) among children aged 1–9 years below
5% at the sub-district level, as determined by an additional round of surveys limited within districts where TF prevalence is
below 10%. We conducted impact surveys powered to estimate prevalence simultaneously at the sub-district and district in
two zones of Amhara, Ethiopia to determine whether MDA could be stopped.
Methodology: Seventy-two separate population-based, sub-district surveys were conducted in 25 districts. In each survey
all residents from 10 randomly selected clusters were screened for clinical signs of trachoma. Data were weighted according
to selection probabilities and adjusted for correlation due to clustering.
Principal Findings: Overall, 89,735 residents were registered from 21,327 households of whom 72,452 people (80.7%) were
examined. The prevalence of TF in children aged 1–9 years was below 5% in six sub-districts and two districts. Sub-district
level prevalence of TF in children aged 1–9 years ranged from 0.9–76.9% and district-level from 0.9–67.0%. In only one district was the prevalence of trichiasis below 0.1%.
