Factors associated with the effectiveness of antibiotic mass drug administration (MDA) in Ethiopia and Niger: an individual participant data (IPD) meta-analysis

Factors associated with the effectiveness of antibiotic mass drug administration (MDA) in Ethiopia and Niger: an individual participant data (IPD) meta-analysis

Family in Niger
Photo credit Stephan Gladieu, World Bank

Considerable progress has been made in decreasing endemicity in regions affected by trachoma through the implementation of the SAFE strategy (Surgery, Antibiotics, Facial cleanliness and Environmental improvement). More than 15 countries have successfully achieved trachoma elimination status. The active trachoma criterion for elimination as a public health problem is a prevalence of “trachomatous inflammation—follicular” (TF) in 1–9-year-olds < 5%, sustained for at least two years in the absence of antibiotic mass drug administration (MDA) [1]. However, in October 2022, trachoma remains endemic in 25 countries on the African continent [2]. 

The impact of the SAFE strategy can vary, and for some places, it has been difficult to achieve elimination status despite continuous years of MDA of azithromycin [3]. Active trachoma is a major public health problem in both Ethiopia and Niger, and it is evident that some districts are experiencing both persistent TF and recrudescent TF following the implementation of A, F and E interventions [1].

Recently conducted systematic reviews identified several MDA studies of azithromycin in these two countries with extensive follow-up and a wide range of baseline trachoma prevalence and effectiveness reported [4-5]. However, those reviews concluded that an aggregated data meta-analysis was not possible due to the heterogeneity of reported outcomes.

IDDO, in collaboration with its expert stakeholder group, has therefore proposed to collate individual patient data (IPD) from the primary studies and conduct an IPD meta-analysis to explore patient and environmental risk factors associated with the effectiveness of MDA. This collaborative Study Group will aim to carry out IPD meta-analysis of cluster randomized controlled trials and observational studies conducted in Ethiopia and Niger. 

An update to the published systematic reviews will be conducted to identify recent eligible studies (PROSPERO registration: CRD42023408078).


The specific objectives are:

  1. To identify factors associated with greater or lesser effectiveness of antibiotic MDA in Ethiopia and Niger by conducting an IPD meta-analysis. 
  2. To evaluate AMR after MDA with antibiotics, provided there are relevant data available.
Essential inclusion criteria
  • Studies investigating antibiotic MDA to control ocular Chlamydia trachomatis infection and active trachoma.
  • Conducted in two trachoma-endemic countries with identified recrudescence: Ethiopia and Niger.
  • Measured active trachoma prevalence and/or ocular C. trachomatis infection at baseline and post-intervention at any time point from 6 months.
  • IPD or, if IPD are not available, cluster-level aggregated data available at baseline and post-MDA.
  • In IPD data, cluster identifiers for each individual.
  • Study dates.
  • Study site information.
  • Details of the drug regimens adopted including frequency and dosage of administration. 
  • Details of diagnostic testing (type of C. trachomatis infection system and clinical grading system used)
  • Details of additional interventions against trachoma (if any).
Desirable criteria
  • Participant information: age, sex, pre-existing conditions.
  • Household/living environment information.
  • AMR information at baseline and after MDA.
  • Details of methodology: cluster selection, blinding, sample size estimation, estimation of baseline prevalence.
Data standardisation and analysis

Data will be uploaded to IDDO’s secure repository environment where IDDO will standardise datasets according to the Statistical Analysis Plan and pool all primary datasets into a single database of quality-assured individual patient data. All data submissions to the repository will remain under the full control of data contributors.

The primary outcome will be the prevalence of Trachoma after the MDA administration, at 6 months, and at other time points as available in the data. A detailed statistical analysis plan will be developed and shared with Study Group members for their comments before the curation of the shared datasets is finalised.

Study group governance

The Study Group consists of participating investigators who have contributed relevant datasets to this pooled analysis. Datasets remain the property of the investigator. The Study Group collectively make decisions with respect to including additional studies, data analysis and plans for publication, in line with the IDDO Publication Policy. IDDO will coordinate research activities with Study Group members and the drafting of publications and reports for group review. The IDDO statistician(s) will be responsible for statistical analyses.

For further information please contact Lien.Tran@iddo.org or Matthew.Brack@iddo.org


1. World Health Organization. (‎2022)‎. Informal consultation on end-game challenges for trachoma elimination, Task Force for Global Health, Decatur, United States of America, 7–9 December 2021. World Health Organization. https://apps.who.int/iris/handle/10665/363591

2. World Health Organization. (n.d.). Malawi eliminates trachoma as a public health problem. World Health Organization. Retrieved October 22, 2022, from https://www.who.int/news/item/21-09-2022-malawi-eliminates-trachoma-as-a-public-health-problem

3. Renneker, Kristen K et al. Global progress toward the elimination of active trachoma: an analysis of 38 countries. The Lancet Global Health, Volume 10, Issue 4, e491 – e500. DOI: 10.1016/S2214-109X(22)00050-X

4. Evans JR, Solomon AW, Kumar R, Perez Á, Singh BP, Srivastava RM, Harding‐Esch E. Antibiotics for trachoma. Cochrane Database of Systematic Reviews 2019, Issue 9. Art. No.: CD001860. DOI: 10.1002/14651858.CD001860.pub4

5. Xiong T, Yue Y, Li WX, Choonara I, Qazi S, Chen HJ, Tang J, Shi J, Wang H, Zeng LN, Xia B, Qiao LN, Qu Y, Mu DZ. Effectiveness of azithromycin mass drug administration on trachoma: a systematic review. Chin Med J (Engl). 2021 Sep 16;134(24):2944-2953. doi: 10.1097/CM9.0000000000001717. PMID: 34665571; PMCID: PMC8710348.