Format

Send to:

Choose Destination
See comment in PubMed Commons below
Lancet. 2009 Mar 28;373(9669):1111-8. doi: 10.1016/S0140-6736(09)60323-8.

Assessment of herd protection against trachoma due to repeated mass antibiotic distributions: a cluster-randomised trial.

Author information

  • 1FI Proctor Foundation, University of California, San Francisco, USA.

Abstract

BACKGROUND:

Trachoma-control programmes distribute oral azithromycin to treat the ocular strains of chlamydia that cause the disease and to control infection. Theoretically, elimination of infection is feasible if untreated individuals receive an indirect protective effect from living in repeatedly treated communities, which is similar to herd protection in vaccine programmes. We assessed indirect protection against trachoma with mass azithromycin distributions.

METHODS:

In a cluster randomised trial, 24 subkebeles (government-defined units) in Amhara, Ethiopia, were randomised, with use of a simple random sample, to distribution four times per year of single-dose oral azithromycin to children aged 1-10 years (12 subkebeles, 4764 children), or to delayed treatment until after the study (control; 12 subkebeles, 6014 children). We compared the prevalence of ocular chlamydial infection in untreated individuals 11 years and older between baseline and 12 months in the treated subkebeles, and at 12 months between the treated and control subkebeles. Health-care and laboratory personnel were blinded to study group. Analysis was intention to treat. The study is registered with clinicaltrials.gov, number NCT00322972.

FINDINGS:

At 12 months, 637 children aged 1-10 years and 561 adults and children aged 11 years and older were analysed in the children-treated group, and 618 and 550, respectively, in the control group. The mean prevalence of infection in children decreased from 48.4% (95% CI 42.9-53.9) to 3.6% (0.8-6.4) after four mass treatments. At 12 months, the mean prevalence of infection in the untreated age group (>/=11 years) was 47% (95% CI 33-57) less than baseline (p=0.002), and 35% (95% CI 1-57) less than that in untreated communities (p=0.04).

INTERPRETATION:

Frequent treatment of children, who are a core group for transmission of trachoma, could eventually eliminate infection from the entire community. Herd protection is offered by repeated mass antibiotic treatments, providing a strategy for elimination of a bacterial disease when an effective vaccine is unavailable.

FUNDING:

National Institutes of Health.

PMID:
19329003
[PubMed - indexed for MEDLINE]
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Elsevier Science
    Loading ...
    Write to the Help Desk