Comparison of the most recent prevalence estimates for trachomatous inflammation—Follicular (TF) in 1–9-year-olds, Malawi, in (a) 2014 and (b) 2016 (after the impact surveys reported here, undertaken following one round of azithromycin MDA).

<p>Comparison of the most recent prevalence estimates for trachomatous inflammation—Follicular (TF) in 1–9-year-olds, Malawi, in (a) 2014 and (b) 2016 (after the impact surveys reported here, undertaken following one round of azithromycin MDA).</p

Evaluation unit population sizes, number of 1–9-year-old children examined, and trachomatous inflammation—Follicular (TF) prevalence in 1–9-year-olds, impact surveys, Malawi, May–August 2016.

<p>Evaluation unit population sizes, number of 1–9-year-old children examined, and trachomatous inflammation—Follicular (TF) prevalence in 1–9-year-olds, impact surveys, Malawi, May–August 2016.</p

One round of azithromycin MDA adequate to interrupt transmission in districts with prevalence of trachomatous inflammation—follicular of 5.0-9.9%: Evidence from Malawi

<div><p>Background</p><p>As highly trachoma-endemic countries approach elimination, some districts will have prevalences of trachomatous inflammation–follicular in 1–9-year-olds (TF_1-9) of 5.0–9.9%. The World Health Organization (WHO) previously recommended that in such districts, TF prevalence be assessed in each sub-district (groupings of at least three villages), with three rounds of azithromycin treatment offered to any sub-district in which TF≥10%. Given the large number of endemic districts worldwide and the human and financial resources required to conduct surveys, this recommendation may not be practical. In a group of 8 Malawi districts with baseline TF prevalences of 5.0–9.9%, the Malawi Ministry of Health administered one round of azithromycin mass treatment, to the whole of each district, achieving mean coverage of ~80%. Here, we report impact surveys conducted after that treatment.</p><p>Methods</p><p>We undertook population-based trachoma surveys in 18 evaluation units of the 8 treated districts, at least 6 months after the MDA. The standardized training package and survey methodologies of Tropical Data, which conform to WHO recommendations, were used.</p><p>Results</p><p>Each of the 18 evaluation units had a TF_1-9 prevalence <5.0%.</p><p>Conclusion</p><p>The study demonstrates that in Malawi districts with TF of 5.0–9.9%, one round of azithromycin MDA with ~80% coverage associates with a reduction in TF prevalence to <5%. Further evidence for this approach should be collected elsewhere.</p></div

Trachomatous inflammation—Follicular (TF) prevalence at baseline and at impact survey, selected districts, Malawi, 2013–2016.

<p>Trachomatous inflammation—Follicular (TF) prevalence at baseline and at impact survey, selected districts, Malawi, 2013–2016.</p

Tropical Data: Approach and Methodology as Applied to Trachoma Prevalence Surveys

Population-based prevalence surveys are essential for decision-making on interventions to achieve trachoma elimination as a public health problem. This paper outlines the methodologies of Tropical Data, which supports work to undertake those surveys. Tropical Data is a consortium of partners that supports health ministries worldwide to conduct globally standardised prevalence surveys that conform to World Health Organization recommendations. Founding principles are health ministry ownership, partnership and collaboration, and quality assurance and quality control at every step of the survey process. Support covers survey planning, survey design, training, electronic data collection and fieldwork, and data management, analysis and dissemination. Methods are adapted to meet local context and needs. Customisations, operational research and integration of other diseases into routine trachoma surveys have also been supported. Between 29th February 2016 and 24th April 2023, 3373 trachoma surveys across 50 countries have been supported, resulting in 10,818,502 people being examined for trachoma. This health ministry-led, standardised approach, with support from the start to the end of the survey process, has helped all trachoma elimination stakeholders to know where interventions are needed, where interventions can be stopped, and when elimination as a public health problem has been achieved. Flexibility to meet specific country contexts, adaptation to changes in global guidance and adjustments in response to user feedback have facilitated innovation in evidence-based methodologies, and supported health ministries to strive for global disease control targets.</p