Cohort and age effects of mass drug administration on prevalence of Trachoma: A longitudinal study in rural Tanzania

Research output: Contribution to journalArticle

Abstract

Purpose. Mass drug administration (MDA) is part of the SAFE strategy for trachoma elimination. This study examined the effect of three annual MDAs on prevalence of trachoma among 13 longitudinal cohorts of Tanzanian children. Methods. Children younger than 10 years were assigned to cohorts based on age at baseline and followed annually for 3 years, with newborns assigned to new cohorts over time. Annual MDA consisted of topical tetracycline for children younger than 6 months and oral azithromycin for those 6 months and older. Follicular trachoma (TF) and Chlamydia trachomatis infection status were assessed annually before the next MDA. Prevalence and risk factors for TF and infection at each age were compared across cohorts. Results. At each survey, most age groups and cohorts had MDA coverage of more than 80% and showed decreased TF prevalence after every MDA. One cohort had consistently lower coverage, higher-than-expected TF and infection at ages 6 and 7, and elevated risk of TF at age 7 relative to the preceding cohort in spite of receiving one additional MDA (odds ratio 2.3, 95% confidence interval 1.0-5.2). Cohorts aged 1 or older at baseline generally showed reductions in TF and infection after each MDA, whereas younger cohorts showed decreased infection but increased TF over time. Successive cohorts of never-treated children younger than 1 year showed sequential TF and infection reductions with each MDA (P <0.001). Conclusions. Multiple MDAs significantly reduce trachoma prevalence and appear to increasingly protect children born into these communities. The youngest children show declining/stable rates of infection but increasing rates of trachoma, which may reflect longer duration of clinical signs.

Original languageEnglish (US)
Pages (from-to)2307-2314
Number of pages8
JournalInvestigative Ophthalmology and Visual Science
Volume55
Issue number4
DOIs
StatePublished - Jan 21 2014

Fingerprint

Trachoma
Cohort Effect
Tanzania
Longitudinal Studies
Pharmaceutical Preparations
Infection
Topical Administration
Chlamydia Infections
Azithromycin
Chlamydia trachomatis
Tetracycline
Age Groups
Odds Ratio
Newborn Infant
Confidence Intervals

Keywords

  • Cohort study
  • Mass drug administration (MDA)
  • Populationbased study
  • Tanzania
  • Trachoma

ASJC Scopus subject areas

  • Ophthalmology
  • Sensory Systems
  • Cellular and Molecular Neuroscience

Cite this

@article{7661629e356e46cdb88d20450e411651,
title = "Cohort and age effects of mass drug administration on prevalence of Trachoma: A longitudinal study in rural Tanzania",
abstract = "Purpose. Mass drug administration (MDA) is part of the SAFE strategy for trachoma elimination. This study examined the effect of three annual MDAs on prevalence of trachoma among 13 longitudinal cohorts of Tanzanian children. Methods. Children younger than 10 years were assigned to cohorts based on age at baseline and followed annually for 3 years, with newborns assigned to new cohorts over time. Annual MDA consisted of topical tetracycline for children younger than 6 months and oral azithromycin for those 6 months and older. Follicular trachoma (TF) and Chlamydia trachomatis infection status were assessed annually before the next MDA. Prevalence and risk factors for TF and infection at each age were compared across cohorts. Results. At each survey, most age groups and cohorts had MDA coverage of more than 80{\%} and showed decreased TF prevalence after every MDA. One cohort had consistently lower coverage, higher-than-expected TF and infection at ages 6 and 7, and elevated risk of TF at age 7 relative to the preceding cohort in spite of receiving one additional MDA (odds ratio 2.3, 95{\%} confidence interval 1.0-5.2). Cohorts aged 1 or older at baseline generally showed reductions in TF and infection after each MDA, whereas younger cohorts showed decreased infection but increased TF over time. Successive cohorts of never-treated children younger than 1 year showed sequential TF and infection reductions with each MDA (P <0.001). Conclusions. Multiple MDAs significantly reduce trachoma prevalence and appear to increasingly protect children born into these communities. The youngest children show declining/stable rates of infection but increasing rates of trachoma, which may reflect longer duration of clinical signs.",
keywords = "Cohort study, Mass drug administration (MDA), Populationbased study, Tanzania, Trachoma",
author = "Nakul Shekhawat and Harran Mkocha and Beatriz Munoz and Gaydos, {Charlotte A} and Laura Dize and Quinn, {Thomas C} and West, {Sheila K}",
year = "2014",
month = "1",
day = "21",
doi = "10.1167/iovs.13-12701",
language = "English (US)",
volume = "55",
pages = "2307--2314",
journal = "Investigative Ophthalmology and Visual Science",
issn = "0146-0404",
publisher = "Association for Research in Vision and Ophthalmology Inc.",
number = "4",

}

TY - JOUR

T1 - Cohort and age effects of mass drug administration on prevalence of Trachoma

T2 - A longitudinal study in rural Tanzania

AU - Shekhawat, Nakul

AU - Mkocha, Harran

AU - Munoz, Beatriz

AU - Gaydos, Charlotte A

AU - Dize, Laura

AU - Quinn, Thomas C

AU - West, Sheila K

PY - 2014/1/21

Y1 - 2014/1/21

N2 - Purpose. Mass drug administration (MDA) is part of the SAFE strategy for trachoma elimination. This study examined the effect of three annual MDAs on prevalence of trachoma among 13 longitudinal cohorts of Tanzanian children. Methods. Children younger than 10 years were assigned to cohorts based on age at baseline and followed annually for 3 years, with newborns assigned to new cohorts over time. Annual MDA consisted of topical tetracycline for children younger than 6 months and oral azithromycin for those 6 months and older. Follicular trachoma (TF) and Chlamydia trachomatis infection status were assessed annually before the next MDA. Prevalence and risk factors for TF and infection at each age were compared across cohorts. Results. At each survey, most age groups and cohorts had MDA coverage of more than 80% and showed decreased TF prevalence after every MDA. One cohort had consistently lower coverage, higher-than-expected TF and infection at ages 6 and 7, and elevated risk of TF at age 7 relative to the preceding cohort in spite of receiving one additional MDA (odds ratio 2.3, 95% confidence interval 1.0-5.2). Cohorts aged 1 or older at baseline generally showed reductions in TF and infection after each MDA, whereas younger cohorts showed decreased infection but increased TF over time. Successive cohorts of never-treated children younger than 1 year showed sequential TF and infection reductions with each MDA (P <0.001). Conclusions. Multiple MDAs significantly reduce trachoma prevalence and appear to increasingly protect children born into these communities. The youngest children show declining/stable rates of infection but increasing rates of trachoma, which may reflect longer duration of clinical signs.

AB - Purpose. Mass drug administration (MDA) is part of the SAFE strategy for trachoma elimination. This study examined the effect of three annual MDAs on prevalence of trachoma among 13 longitudinal cohorts of Tanzanian children. Methods. Children younger than 10 years were assigned to cohorts based on age at baseline and followed annually for 3 years, with newborns assigned to new cohorts over time. Annual MDA consisted of topical tetracycline for children younger than 6 months and oral azithromycin for those 6 months and older. Follicular trachoma (TF) and Chlamydia trachomatis infection status were assessed annually before the next MDA. Prevalence and risk factors for TF and infection at each age were compared across cohorts. Results. At each survey, most age groups and cohorts had MDA coverage of more than 80% and showed decreased TF prevalence after every MDA. One cohort had consistently lower coverage, higher-than-expected TF and infection at ages 6 and 7, and elevated risk of TF at age 7 relative to the preceding cohort in spite of receiving one additional MDA (odds ratio 2.3, 95% confidence interval 1.0-5.2). Cohorts aged 1 or older at baseline generally showed reductions in TF and infection after each MDA, whereas younger cohorts showed decreased infection but increased TF over time. Successive cohorts of never-treated children younger than 1 year showed sequential TF and infection reductions with each MDA (P <0.001). Conclusions. Multiple MDAs significantly reduce trachoma prevalence and appear to increasingly protect children born into these communities. The youngest children show declining/stable rates of infection but increasing rates of trachoma, which may reflect longer duration of clinical signs.

KW - Cohort study

KW - Mass drug administration (MDA)

KW - Populationbased study

KW - Tanzania

KW - Trachoma

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U2 - 10.1167/iovs.13-12701

DO - 10.1167/iovs.13-12701

M3 - Article

C2 - 24448262

AN - SCOPUS:84898414656

VL - 55

SP - 2307

EP - 2314

JO - Investigative Ophthalmology and Visual Science

JF - Investigative Ophthalmology and Visual Science

SN - 0146-0404

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ER -