Trachoma, caused by particular serovars of Chlamydia trachomatis, is the leading infectious cause of blindness. Infection is transmitted by ocular and nasal secretions that are passed from person to person on fingers and fomites (such as hard surfaces and clothing) and by eye-seeking flies (particularly Musca sorbens). Ophthalmic infection is associated with inflammatory conjunctivitis, known as “active trachoma”. Repeated episodes of active trachoma can scar the inner side of the eyelids. In some individuals, this leads to trachomatous trichiasis (TT), in which one or more eyelashes from the upper eyelid touch the eye. TT is extremely painful. It can be corrected surgically but, if left untreated, may lead to corneal opacification, vision impairment and blindness.
Trachoma can be eliminated as a public health problem with a set of interventions known as the “SAFE strategy”, comprising surgery for TT, antibiotics to clear ocular C. trachomatis infection and facial cleanliness and environmental improvement (particularly improved access to water and sanitation) to reduce C. trachomatis transmission. Surgery should be offered to any individual with TT considered likely to benefit from an operation; the S component of the SAFE strategy is a public health intervention, including active case-finding if necessary, which is recommended when the prevalence of TT “unknown to the health system” is ≥0.2% among people aged ≥15 years. The A, F and E components of SAFE are recommended for districts (usually with populations of 100 000–250 000) in which the prevalence of the active trachoma sign “trachomatous inflammation— follicular” (TF) is ≥5% in children aged 1–9 years. In those districts, all residents should usually be offered antibiotic treatment annually, the planned number of rounds depending on the most recent estimate of TF prevalence. The criteria for elimination of trachoma as a public health problem are: (i) a prevalence of TT unknown to the health system of <0.2% among people aged ≥15 years and (ii) a prevalence of TF of <5% among children aged 1–9 years in each formerly endemic district, plus (iii) evidence that the health system can continue to identify and manage incident cases of TT.
The requirements for these interventions are determined by population-based prevalence surveys in districts suspected of being endemic at baseline. Surveys are repeated at specified intervals after initiation of interventions. In particular, it is recommended that impact surveys be undertaken at least 6 months after the last planned annual round of antibiotic mass drug administration, in order to determine whether treatment should be continued or can safely be stopped. This report summarizes application of the SAFE strategy against trachoma during 2023. It includes estimates of the global population at risk of trachoma blindness based on district-by-district data submitted to WHO by national programmes. Summarizing the epidemiological situation in this way is inherently complex because, for any district, up to 3 serial estimates of prevalence may be valid at different times during a calendar year. If reported in isolation, TF prevalence estimates from impact surveys done after (but in the same calendar year as) antibiotic treatment might (i) be interpreted as indicating that the previous treatment was unjustified and (ii) result in division-by-zero errors in calculations of antibiotic coverage against need. To avoid these problems, the highest TF prevalence estimated for each district in a calendar year (regardless of the date in the year on which that estimate was valid) was used to generate a rolling peak prevalence estimate for 1 January–31 December 2023 (Table 1); these figures were used as the denominators for calculating intervention coverage. To provide the most up-to-date snapshot of progress towards global elimination of trachoma as a public health problem, summaries based on district-level prevalence estimates held in the GET202013 database as of 15 April 2024 are also included (Table 1). The point-prevalence snapshot for 15 April 2024 can be compared with that of 25 April 2023.
LA - ENG M3 - Report N2 -Trachoma, caused by particular serovars of Chlamydia trachomatis, is the leading infectious cause of blindness. Infection is transmitted by ocular and nasal secretions that are passed from person to person on fingers and fomites (such as hard surfaces and clothing) and by eye-seeking flies (particularly Musca sorbens). Ophthalmic infection is associated with inflammatory conjunctivitis, known as “active trachoma”. Repeated episodes of active trachoma can scar the inner side of the eyelids. In some individuals, this leads to trachomatous trichiasis (TT), in which one or more eyelashes from the upper eyelid touch the eye. TT is extremely painful. It can be corrected surgically but, if left untreated, may lead to corneal opacification, vision impairment and blindness.
Trachoma can be eliminated as a public health problem with a set of interventions known as the “SAFE strategy”, comprising surgery for TT, antibiotics to clear ocular C. trachomatis infection and facial cleanliness and environmental improvement (particularly improved access to water and sanitation) to reduce C. trachomatis transmission. Surgery should be offered to any individual with TT considered likely to benefit from an operation; the S component of the SAFE strategy is a public health intervention, including active case-finding if necessary, which is recommended when the prevalence of TT “unknown to the health system” is ≥0.2% among people aged ≥15 years. The A, F and E components of SAFE are recommended for districts (usually with populations of 100 000–250 000) in which the prevalence of the active trachoma sign “trachomatous inflammation— follicular” (TF) is ≥5% in children aged 1–9 years. In those districts, all residents should usually be offered antibiotic treatment annually, the planned number of rounds depending on the most recent estimate of TF prevalence. The criteria for elimination of trachoma as a public health problem are: (i) a prevalence of TT unknown to the health system of <0.2% among people aged ≥15 years and (ii) a prevalence of TF of <5% among children aged 1–9 years in each formerly endemic district, plus (iii) evidence that the health system can continue to identify and manage incident cases of TT.
The requirements for these interventions are determined by population-based prevalence surveys in districts suspected of being endemic at baseline. Surveys are repeated at specified intervals after initiation of interventions. In particular, it is recommended that impact surveys be undertaken at least 6 months after the last planned annual round of antibiotic mass drug administration, in order to determine whether treatment should be continued or can safely be stopped. This report summarizes application of the SAFE strategy against trachoma during 2023. It includes estimates of the global population at risk of trachoma blindness based on district-by-district data submitted to WHO by national programmes. Summarizing the epidemiological situation in this way is inherently complex because, for any district, up to 3 serial estimates of prevalence may be valid at different times during a calendar year. If reported in isolation, TF prevalence estimates from impact surveys done after (but in the same calendar year as) antibiotic treatment might (i) be interpreted as indicating that the previous treatment was unjustified and (ii) result in division-by-zero errors in calculations of antibiotic coverage against need. To avoid these problems, the highest TF prevalence estimated for each district in a calendar year (regardless of the date in the year on which that estimate was valid) was used to generate a rolling peak prevalence estimate for 1 January–31 December 2023 (Table 1); these figures were used as the denominators for calculating intervention coverage. To provide the most up-to-date snapshot of progress towards global elimination of trachoma as a public health problem, summaries based on district-level prevalence estimates held in the GET202013 database as of 15 April 2024 are also included (Table 1). The point-prevalence snapshot for 15 April 2024 can be compared with that of 25 April 2023.
PY - 2024 SP - 1 EP - 18 TI - WHO Alliance for the Global Elimination of Trachoma: progress report on elimination of trachoma, 2023 UR - https://iris.who.int/bitstream/handle/10665/378195/WER9928-eng-fre.pdf ER -