Single azithromycin dose not enough to eradicate trachoma

A single antibiotic dose may not be sufficient to ward off trachoma recurrences, according to a study.

Researchers found ocular chlamydial infection returned slowly over the course of 24 months, although they acknowledged the trachoma did not return to baseline levels.

Jaya D. Chidambaram, MBBS, and colleagues at the F.I. Proctor Foundation in San Francisco offered all residents in eight selected Ethiopian villages a single dose of oral azithromycin. The residents were then followed for 24 months to determine recurrence rates. An additional 15 untreated villages were randomly chosen at the 12-month mark to assess a secular trend, if one exists.

The main outcome measure was the prevalence of ocular chlamydial infection before treatment in all children between the ages of 1 and 5 from each of the intervention villages, and compared the results to post-treatment at 2, 6, 12, 18 and 24 months. A total of 515 children were examined. The mean prevalence of infection in children decreased from 43.5% before antibiotic treatment to 5.1% after treatment.

Over the course of the follow-up, the infection returned in 11.3% of the population. In seven of the eight villages, infection was higher at 24 months than at 2 months. In the last village, the infection appeared to have been eradicated with the one antibiotic dosing regimen.

“Our results suggest that if infection is not eliminated by a single mass antibiotic treatment, then it predictably returns into the community, at least in this hyperendemic area in 1- to 5-year-old children,” the study authors said. “However, infection comes back slowly and does not approach baseline prevalence even by 2 years.”

The authors said they support repeated treatment or another intervention method to eliminate the infection completely. “A single [azithromycin] treatment will not suffice,” they said.

The study is published in the March issue of Journal of the American Medical Association.