Trachoma and ocular Chlamydia trachomatis were not eliminated three years after two rounds of mass treatment in a trachoma hyperendemic village.

PURPOSE: The World Health Organization recommends mass treatment of trachoma-hyperendemic communities, but there are scant empiric data on the number of rounds of treatment that are necessary for sustainable reductions. The rates of active trachoma and infection with C. trachomatis were determined in a community 3.5 years after two rounds of mass treatment with azithromycin.
METHODS: Maindi village in Tanzania received a first round of mass treatment with azithromycin after a baseline survey for trachoma and infection. All residents aged 6 months and older were offered single-dose treatment with azithromycin (excluding pregnant women with no clinical trachoma, who were offered topical tetracycline). The residents were followed over an 18-month period, and, according to similar treatment criteria, were offered retreatment at 18 months. Five years after baseline (3.5 years after the second round of mass treatment), a new census and survey of current residents for trachoma and infection was conducted. Children are the sentinel markers of infection and trachoma in communities, so data are presented specifically for ages 0 to 7 years (preschool age) and 8 to 16 years.
RESULTS: Treatment coverage was above 80% for all ages in the first round, and highest (90%) in preschool-aged children. Second-round coverage was lower, <70%, and 70% in preschool-aged children. At 5 years, trachoma rates were still lower than baseline, ranging from 45% in those aged 0 to 3 years to 8% in those aged 11 to 15 years (compared with 81% and 39% at baseline, respectively). Infection rates at baseline ranged from 71% to 57%, but were 27% to 17% at 5 years after two rounds of mass treatment. At 5 years, there were no differences in trachoma or infection rates, when comparing new residents who came after the second mass treatment with those who had been resident in the village during both rounds (P > 0.05). Infection rates were lower in those who had been treated twice or at 18 months than in those treated only at baseline or never treated.
CONCLUSIONS: Although mass treatment appears to be associated with lower disease and infection rates in the long term, trachoma and C. trachomatis infection were not eliminated in this trachoma hyperendemic village 3.5 years after two rounds of mass treatment. Continued implementation of the SAFE strategy in this environment is needed.