A secondary analysis to determine countries and districts eligible for documented full geographic coverage for trichiasis case finding and outreaches

Abstract

Background

The World Health Organization recommends house-to-house case searches as an option to evidence whether the elimination of trachomatous trichiasis (TT) has been reached. We sought to determine the number of trachoma-endemic countries and districts that will require either documented full geographic coverage (DFGC) or TT-only surveys.

Methods

We conducted a secondary analysis of data from the Trachoma Atlas to identify evaluation units (EUs) that require house-to-house case searches or TT-only surveys to demonstrate achievement of the elimination of TT.

Results

There were 1710 EUs with TT above the elimination prevalence target in all trachoma-endemic countries. Of those EUs, 852 (49.8%) do not have a future survey planned and will therefore potentially have to evidence through DFGC or TT-only surveys whether the elimination prevalence target for TT has been reached.

Conclusion

Of the large number of EUs that require TT-related activities, nearly half of them will need to evidence that every household in the EU has been visited by a case finder and all confirmed cases managed. Given that this is a relatively new way to evidence elimination, and countries face different sociopolitical challenges, cross-country learning and improved guidance is key to support global elimination.

Introduction

The World Health Organization (WHO) specifies the following criteria for elimination of trachoma as a public health problem:¹

• • A prevalence of trachomatous inflammation–follicular in children ages 1–9 y of <5%, sustained for at least 2 y in the absence of ongoing antibiotic mass treatment, in each formerly endemic district.

• • A prevalence of trachomatous trichiasis (TT) unknown to the health system in ≥15-year-olds of <0.2% following a trachoma prevalence survey.

• • Written evidence that the health system can identify and manage incident cases of TT using defined strategies, with evidence of appropriate financial resources to implement those strategies.

The 4th WHO Global Scientific Meeting on Trachoma, held in November 2018, recommended that to assess whether the elimination prevalence target for TT has been reached, national programs may use² population-based prevalence surveys powered at the evaluation unit (EU) level (i.e. populations of 100 000–250 000 people), house-to-house case searches (which could be integrated with other public health activities) or a combination of data from multiple adjacent EUs.

Documented full geographic coverage (DFGC)

House-to-house case finding has been used in various programs for a number of years. The Guinea worm eradication program has long used this approach and more recently Ghana and Malawi both evidenced TT elimination in some EUs using documented house-to-house case finding instead of a prevalence survey. Their trachoma elimination dossiers were validated in 2018 and 2022, respectively.^3,4

Various names have been used to describe the approach, including sweeping, ratissage (in French-speaking countries), house-to-house sweeping and case finder geographical coverage, among others. The addition of this option at the 2018 WHO Global Scientific Meeting on Trachoma² to demonstrate elimination has increased focus on the approach, however, no additional guidance has been provided.

The International Coalition for Trachoma Control (ICTC) has developed resources to support countries with the SAFE strategy (surgery to treat the advanced, blinding stage of the disease [trichiasis], antibiotics to treat active infection, facial cleanliness and environmental improvements, specifically increasing access to water and sanitation). The 2016 Training Curriculum for Trichiasis Case Identifiers lists the roles and responsibilities of case finders and provides a template for registration of suspect trichiasis patients identified by case finders during house-to-house visits.⁵

Building on existing guidance and experience, Sightsavers adopted the nomenclature DFGC for a community mobilisation strategy used by trachoma elimination programs to guarantee that all people suspected of having trichiasis are identified at the household level in each community and offered corrective services. The emphasis on documentation is to guarantee that a trachoma program puts in place rigorous evidence of house-to-house case searches and outreaches to guarantee acceptability of the documentation as part of the district-level trachoma elimination dossier preparation.⁶

This approach aims to ensure that every person >15 y of age in every household in a TT-endemic EU in trachoma-endemic countries has been looked at for suspected trichiasis (by case finders). These suspected cases are then examined by trained health personnel (e.g. trichiasis surgeons or ophthalmic nurses) to confirm whether they have TT or not. Once confirmed, they are then considered ‘known to the health system’. They are offered the appropriate management—usually surgery or epilation—and if they refuse management, they are counselled and visited again after a short period.⁵

In this study we sought to determine the number of countries and EUs in trachoma-endemic countries that will require either DFGC or TT-only surveys to document elimination of trachoma as a public health problem. We expect that these data will be vital for identifying and creating urgency in countries that will need to prepare robust FGC documentation as part of their trachoma elimination dossier. This should stimulate shared learning and improvement of preferred practices on FGC, helping countries mobilise resources to achieve elimination of trichiasis as a public health problem.

Methods

We conducted a secondary analysis of data made available from the Trachoma Atlas in October 2022 to identify EUs that require house-to-house case searches or TT-only surveys to demonstrate achievement of the elimination of trichiasis as a public health problem.⁷

Using Excel (Microsoft, Redmond, WA, USA), we combined country trachoma survey data sets and then used pivot tables to extract data on EUs that require FGC to demonstrate elimination of TT as a public health problem.

We included EUs with a prevalence of TT unknown to the health system of ≥0.20%. Among this group we identified both EUs that had a baseline survey in which trachomatous inflammation–follicular (TF) in children ages 1–9 y was <5% (thereby not requiring interventions for active trachoma) and EUs in which a pre-elimination surveillance survey showed the prevalence of TF was <5%. We included trachoma baseline surveys done as part of the Global Trachoma Mapping Project from 2012 onwards, which included trachoma surveillance and TT-only surveys. We excluded EUs with scheduled trachoma impact surveys or surveillance surveys. While Australia is listed as a trachoma-endemic country, we limited our analysis to low- and middle-income countries (LMICs).

We grouped countries into geographical regions similar to the grouping by Renneker et al.⁸ For analysis convenience, countries in Africa were grouped according to regional groupings. The East African grouping included East African Community and Intergovernmental Authority on Development countries⁹ (Table 1).

Table 1.

Countries that will require house-to-house trichiasis case-finding or TT only survey to evidence elimination of trachomatous trichiasis as a public health problem

Country	# of EU yet to reach elimination threshold (TF and or TT)	# of EU yet to reach elimination threshold (TT alone irrespective)	# of EU above threshold for TT with no further survey planned	% of EUs above TT threshold with no further survey planned against those yet to reach elimination threshold (TF and/or TT)
Global	1935	1710	852	44%
Africa	1740	1619	796	46%
Central Africa	155	132	70	45%
Cameroon	12	12	9	75%
Central African Republic	24	23	0	0%
Chad	46	46	37	80%
Democratic Republic of the Congo	73	51	24	33%
Eastern Africa	1014	962	320	32%
Eritrea	14	14	13	93%
Ethiopia	721	672	111	15%
Kenya	33	32	17	52%
South Sudan	42	42	5	12%
Sudan	80	78	65	81%
Tanzania	76	76	66	87%
Uganda	48	48	43	90%
Northern Africa	80	80	71	89%
Algeria	69	69	69	100%
Egypt	4	4	0	0%
Libya	2	2	2	100%
Morocco	5	5	0	0%
Southern Africa	102	78	44	43%
Angola	10	0	0	0%
Malawi	5	5	5	100%
Mozambique	46	40	19	41%
Zambia	26	24	16	62%
Zimbabwe	15	9	4	27%
Western Africa	389	367	291	75%
Benin	11	11	11	100%
Burkina Faso	17	17	13	76%
Cote d'Ivoire	16	1	1	6%
Ghana	17	17	0	0%
Guinea	6	6	6	100%
Guinea Bissau	4	4	4	100%
Mali	22	22	18	82%
Niger	49	43	25	51%
Nigeria	188	187	154	82%
Senegal	58	58	58	100%
Togo	1	1	1	100%
Latin America	16	7	5	31%
Brazil	2	2	2	100%
Colombia	6	1	0	0%
Guatemala	4	4	3	75%
Peru	4	0	0	0%
Asia	86	59	51	59%
Afghanistan	8	0	0	0%
India	6	6	6	100%
Nepal	2	2	2	100%
Pakistan	5	5	5	100%
Viet Nam	13	13	11	85%
Yemen	52	33	27	52%
Pacific Islands	89	25	0	0%
Kiribati	24	24	0	0%
Nauru	1	1	0	0%
Papua New Guinea	12	0	0	0%
Solomon Islands	46	0	0	0%
Vanuatu	6	0	0	0%
Oceania	4	0	0	0%
Australia	4	0	0	0%

TF: Trachomatous Inflammation - Follicular; TT: Trachomatous Trichiasis; EU: Evaluation Unit

Results

As of October 2022, there were 1710 EUs with TT unknown to the health system ≥0.2% in all known trachoma-endemic LMICs globally (Table 1). Of those EUs, 852 (49.8%) do not have a future survey planned and will therefore potentially have to assess whether the elimination prevalence threshold for TT has been reached through house-to-house case searches or TT-only surveys. A total of 796 (94%) of the EUs are in Africa. The largest number of EUs not eligible for a future TF survey (154 [18%]) are in Nigeria. While Benin, Ghana, Malawi, Mali, Morocco, Nepal, Togo and Vanuatu appear in our analysis, the WHO has already validated them as having eliminated trachoma as a public health problem.^10,11

Discussion

The analysis shows that of the large number of EUs that require TT-related activities (1710), nearly half of them will need to evidence that every household in the EU has been visited by a case finder and all confirmed cases managed. The identified countries have variable contexts relating to safety and security, conflict, contrasting capacity of health systems, health system disruptions caused by the coronavirus disease 2019 pandemic and varying sociocultural issues at the community level, among other issues.^12–15

Mwangi et al.,¹⁶ in their four-country study, attributed the inability to achieve TT elimination prevalence targets despite FGC interventions in a district to failure by case finders to reach all target households, gaps in case finder capacity to correctly identify trichiasis cases, misdiagnosis of TT, refusal of patients to be examined or to attend outreach and poor documentation of case finding and outreaches.

Ul Hassan et al.,¹⁷ in their study on the efficiency of different community mobilisation approaches in seven African countries, concluded that while DFGC requires more resources to train and deploy trichiasis case finders, the house-to-house case-finding approach provides greater efficiencies than targeted community-level approaches, which tend to attract big crowds but produce only a small number of trichiasis cases.

In addition to the above highlighted issues, the DGFC approach has many other advantages, including stronger evidence (than a prevalence survey) that there are no TT cases unknown to the health system, ensuring no one is left behind, extending the reach of the trachoma program to underserved populations, strengthening health delivery services and strengthening sustainable systems.

The main drawback of DGFC is that case finding in all households in TT-endemic EUs, and the rigorous documentation of the same, requires a large number of resources—both human and financial. While this factor might raise concerns about cost effectiveness of the DGFC approach, it is mitigated by the benefits of reaching every household and guaranteeing that every trichiasis case identified receives required services. Ultimately, DGFC helps reduce the risks of districts failing to achieve elimination prevalence targets for trichiasis in trachoma prevalence surveys and the need for additional costly interventions.

For budgeting purposes there is a need to analyse further the main cost drivers. It may be more relevant to budget for elimination using a unit cost per population/household size of an EU, irrespective of the estimated number of TT cases to manage. This would shift focus away from cost per surgery and allow presentation of the cost of eliminating TT in a district (irrespective of level of prevalence), which may be a clearer presentation of elimination costs for donors and countries—levelling out the cost of the ‘end game’ (where fewer and fewer TT cases are left to be found and managed).

Conclusions

Almost half of the EUs currently above the threshold for TT need to provide evidence of elimination through house-to-house case searches. There is a need to share information on the most efficient and effective ways to carry this out and document it. Trachoma program stakeholders should also prioritise interventions in those districts to gain momentum in trachoma elimination.

The global community would also benefit from further analysis of the cost drivers as well as increasing understanding among governments, local trachoma program stakeholders and donors of the challenges and benefits of demonstrating elimination (of TT) in this way. A collaborative effort by ministries of health, communities in the endemic areas, NGO partners, donors and other stakeholders will be crucial to build on cross-country learning and improved guidance to support global elimination.

Authors’ contributions

MKK and MK developed the study design. MKK, KM and SS contributed to the data analysis and interpretation and wrote the first draft of the manuscript.

Acknowledgements

We are grateful to Teyil Wamyil-Mshelia and Grace Ajege for initial contributions during the design phase of the article. Thanks to Kristen Renneker, at the International Trachoma Initiative, for providing the data for analysis. Secondary data analysis for the purpose of this article was supported through the Accelerate program.

Funding

The production of this manuscript was funded by a consortium of donors to Sightsavers' Accelerate programme, including Bill and Melinda Gates Foundation, Children's Investment Fund Foundation, The ELMA Foundation, Virgin Unite, and an Anonymous donor. The funders had no role in the writing of the manuscript or the decision to submit it for publication.

Competing interests

MK is a guest editor of this supplement but had no role in the review of this manuscript.

Ethical approval

We conducted a secondary analysis of data made available from the Trachoma Atlas in October 2022. No ethical approval was required.

Data availability

The data that support the findings of this study are available from the corresponding author, MKK, upon reasonable request.