Trachoma: The Last Decade?

This special issue of Ophthalmic Epidemiology is devoted to trachoma, the most common infectious cause of blindness. In previous such issues published by Ophthalmic Epidemiology over the last 8 years, guest editors have noted the momentum being generated towards global elimination of trachoma and expressed optimism for imminent success.^1–4

Our most important message to accompany this latest trachoma special issue is the same: good progress is being made. In April 2023, an estimated 116 million people lived in areas that warrant treatment with antibiotics, facial cleanliness, and environmental improvement for trachoma elimination purposes, and an estimated 1.5 million people had trachomatous trichiasis.⁵ These estimates represent reductions of 92% and 80%, respectively, from the estimates for 2002, and reductions of 7% and 12% since June 2022.⁶ This is positive news for global health.

But we all want progress to be faster. The greater the time taken to achieve our shared targets for trachoma, the greater the number of individuals whose sight will be impaired by it. And, in the last few years, the global trachoma community has become collectively more aware of the issue of persistent and recrudescent active trachoma, realised the paucity of evidence we have to guide decisions on how to manage populations in which these phenomena are manifest, and had to reconsider its approach.⁷ Other challenges persist, too. Indigenous populations,⁸ refugees,^9,10 internally displaced persons,¹¹ populations in areas affected by conflict^12,13 and other special groups all remain hard to reach in many places. There is also the problem of national and sub-national administrative areas that share borders across which there are substantial gradients in active trachoma prevalence; this potentially raises questions related to both the recrudescence of disease and how to undertake surveillance. To accelerate and sustain local success, we should integrate some of the knowledge and skills for delivering trachoma services into primary healthcare systems and community-based people-centred services.¹⁴ We have not yet generated consensus on how surveillance should be undertaken to detect post-validation recrudescence in any context – a separate issue to persistent or recrudescent active trachoma inasmuch as these things are currently defined.⁷

Another important development since publication of the last Ophthalmic Epidemiology trachoma special issue is the postponement of the deadline for global elimination as a public health problem: from 2020 to 2030.¹⁵ For political reasons, we can’t afford to have to do that again.

To that end, work continues on many fronts. As of September 2023, 18 of 62 countries known to be currently or previously trachoma-endemic had been validated as having eliminated trachoma as a public health problem; another five countries require further investigation. Trachoma prevalence estimation is robust and improving, thanks to the continuing support provided to endemic countries by Tropical Data¹⁶; the papers in this issue are testament to that fact, as is the confidence with which we are able to set out the estimates of global disease burden above, and to know that we have a problem from persistent and recrudescent active trachoma in some populations. Work is also ongoing to further develop model-based geostatistics^17,18 to analyse trachoma prevalence survey output, to better understand trachoma in the Pacific Islands^19–21 and the Torres Strait,²² and to consider an expanded role for conjunctival photography,²³ amongst other efforts. Recently, WHO has launched the process of guideline development for the use of serology in trachoma elimination programmes; serology could provide a practical way to undertake integrated surveillance after the cessation of antibiotic MDA.^24–27

Finally, partnership within the trachoma elimination community remains robust. The 24^th meeting of the World Health Organization Alliance for the Global Elimination of Trachoma was a face-to-face event held in Istanbul in April 2023, after several years of postponed and virtual meetings; it was well attended and invigorating. With colleagues around the globe, we look forward to overcoming the remaining hurdles to trachoma elimination and transitioning to a world in which such meetings are no longer important.

Disclaimer

The authors alone are responsible for the views expressed in this publication, and they do not necessarily represent the views, decisions, or policies of the institutions with which they are affiliated. In any reproduction of this article, there should be no suggestion that PAHO, WHO, or this article endorse any specific organization, products, or services. The use of the PAHO or WHO logos is not permitted. This notice should be preserved along with the article’s original URL.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

MISD is a staff member of the Pan American Health Organization (PAHO). AWS is a staffmember of the World Health Organization (WHO).