Mass Drug Administration for Trachoma: How Long Is Not Long Enough? Open Access

Jimenez, Violeta (2014)

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Background: Blinding trachoma is targeted for elimination by 2020 through global intervention with the SAFE strategy. Although annual mass drug administration (MDA) to curb transmission is a cornerstone of this strategy, its effect on different baseline trachoma prevalence levels is poorly characterized. In order to achieve elimination goals, the World Health Organization (WHO) recommends an increase from a minimum of 3 treatment rounds to 5 prior to re-survey if prevalence exceeds 30%, these recommendations are based on expert opinion and grounded in a relatively small evidence base. Assessment of the effectiveness of these recommendations in practice is necessary to guide programming such that elimination by 2020 is ensured.

Methodology/Principal Findings: Data on prevalence and treatment was drawn from cross-sectional surveys in the International Trachoma Initiative's database and matched on location. Of three hundred and eighty one pairs representing baseline and follow-up surveys, MDA was applied in 186, while 113 represented a change in prevalence in the absence of MDA. Regression modeling showed that as baseline prevalence increased, the likelihood that treatment would reduce prevalence decreased significantly. Treatment rounds, skipped years, and length of time before and after treatment started were also significant predictors in multivariate models. Logistic models predicted that even with perfect programmatic continuity, the probability of achieving successful reduction was low for high endemic areas, even with increasing rounds of treatment.


In addition to treatment rounds, quality of treatment cycles and the context in which they occur are important predictors of trachoma prevalence reduction. In particular, care should be taken to ensure uninterrupted treatment. Programmatic recommendations must be strengthened to emphasize uninterrupted treatment, and greater effort must be made to change the underlying conditions in which transmission occurs. There are six years before the 2020 elimination deadline. There is a very low probability of achieving sufficient prevalence reduction in high endemic settings under the current treatment paradigm. More intense treatment strategies are needed in order to guarantee elimination by 2020.

Table of Contents

Table of Contents

Chapter 1: Introduction 1

Context 1

Problem Statement 2

Purpose Statement 4

Chapter 2: Literature Review 6

A Brief History of Trachoma 6

Assessing Trachoma in an Individual 9

Clinical Progression of Disease 9

Diagnosis and Grading of Trachoma 12

Assessing Trachoma Prevalence at the Community Level 18

Transmission and Risk Factors 18

The Interaction Between Age, Incidence, and Prevalence 23

Assessing Trachoma Globally 25

Survey Methodology 25

The Size of the Problem 28

Addressing Trachoma Globally: The SAFE Strategy 31

Surgery 32

Face-Washing and Health Education 34

Environmental Interventions 36

Antibiotics 39

The SAFE Strategy as a Holistic Approach 48

Addressing Trachoma: The End in Sight? 49

Chapter 3: Manuscript 53

Contribution of Student 55

Abstract 56

Keywords 57

Author Summary 57

Introduction 59

Methods 62

Database 62

Data Cleaning and Abstraction 64

Data Analysis 66

Results 68

Discussion 71

References 77

Tables and Figures 83

Conclusions 88

References 94

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