title: Assessment of transmission in trachoma programs over time suggests no short-term loss of immunity.
abstract: Trachoma programs have dramatically reduced the prevalence of the ocular chlamydia that cause the disease. Some have hypothesized that immunity to the infection may be reduced because of program success in reducing the incidence of infection, and transmission may then increase. Longitudinal studies of multiple communities would be necessary to test this hypothesis. Here, we quantify transmission using an estimated basic reproduction number based on 32 communities during the first, second, and third years of an antibiotic treatment program. We found that there is little to no increase in the basic reproduction number over time. The estimated linear trend in the basic reproduction number, [Formula: see text], was found to be -0.025 per year, 95% CI -0.167 to 0.117 per year. We are unable to find evidence supporting any loss of immunity over the course of a 3-year program. This is encouraging, as it allows the possibility that repeated mass antibiotic distributions may eliminate infection from even the most severely affected areas.
authors.affiliation: F.I. Proctor Foundation, University of California, San Francisco, California, USA.
authors.forename: Fengchen
authors.initials: F
authors.lastname: Liu
authors.forename: Travis C
authors.initials: TC
authors.lastname: Porco
authors.forename: Kathryn J
authors.initials: KJ
authors.lastname: Ray
authors.forename: Robin L
authors.initials: RL
authors.lastname: Bailey
authors.forename: Harran
authors.initials: H
authors.lastname: Mkocha
authors.forename: Beatriz
authors.initials: B
authors.lastname: Muñoz
authors.forename: Thomas C
authors.initials: TC
authors.lastname: Quinn
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Lietman
authors.forename: Sheila K
authors.initials: SK
authors.lastname: West
mesh_terms: D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D050936:Basic Reproduction Number; D002675:Child, Preschool; D002692:Chlamydia trachomatis / Q000276:immunology*; D006801:Humans; D007223:Infant; D013997:Time Factors; D014141:Trachoma / Q000188:drug therapy / Q000276:immunology* / Q000635:transmission*
chemical_list: D000900:Anti-Bacterial Agents