Prevalence of latent tuberculosis infection in Asian nations: A systematic review and meta‐analysis

Abstract Background Tuberculosis (TB) is a serious public health concern around the world including Asia. TB burden is high in Asian countries and significant population harbor latent tuberculosis infection(LTBI). Aim This systematic review and meta‐analysis aims to evaluate the prevalence of LTBI in Asian countries. Method We performed a systematic literature search on PubMed, Embase, and ScienceDirect to identify relevant articles published between January 1, 2005, and January 1, 2023 investigating the overall prevalence of latent TB among people of Asia. Subgroup analysis was done for Asian subregions during the study period of 2011 to 2016 and 2017 to 2023, for tuberculin skin test (TST) and interferon gamma release assay (IGRA), respectively, as well as for QuantiFERON‐TB (QFT) and TSPOT TB tests. Der Simonian and Laird's random‐effects model was used to pool the prevalence of LTBI found using TST and IGRA. Result A total of 15 studies were included after a systematic search from standard electronic databases. The analysis showed that the prevalence of latent TB in Asia was 21% (95% confidence interval [CI]: 19%–23%) and 36% (95% CI: 12%–59%) according to IGRAs and TSTs (cut off 10 mm) results, respectively. Based on IGRA, the prevalence of latent TB was 20% (95% CI: 13%–25%) in 2011 to 2016 and 21% (95% CI: 18%–24%) in 2017 to 2023. Using QFT, the prevalence was 19% (95% CI: 17%–22%) and using TSPOT, the prevalence was 26% (95% CI: 21%–31%). According to the United Nations division of Asia, the prevalence was higher for the Southern region and least for the Western region using TST and higher in the South‐Eastern region and least in the Western region using the IGRA test. Conclusion Almost a quarter of the Asian population has LTBI. Its diagnosis often poses a diagnostic challenge due to the unavailability of standard test in certain areas. Given this prevalence, a mass screening program is suggested with the available standard test and public awareness along with anti‐TB regimen should be considered for individuals who test positive. However, for it to be implemented effectively, we need to take the affordability, availability, and cost‐effectiveness of such interventions into account

Village-integrated eye workers for prevention of corneal ulcers in Nepal (VIEW study): a cluster-randomised controlled trial

BackgroundCorneal ulcers are a common cause of blindness in low-income and middle-income countries, usually resulting from traumatic corneal abrasions during agricultural work. Antimicrobial prophylaxis of corneal abrasions can help prevent corneal ulcers, but delays in the initiation of therapy are frequent. We aimed to assess whether a community-based programme for corneal ulcer prevention would reduce the incidence of corneal ulceration.MethodsA cluster-randomised trial was performed in village development committees (VDCs) in Nepal. VDCs in the catchment area of Bharatpur Eye Hospital, Nepal with less than 15 000 people were eligible for inclusion. We randomly assigned (1:1) VDCs to either an intervention group or a control group. In the intervention VDCs, existing female community health volunteers (FCHVs) were trained to diagnose corneal abrasions and provide a 3-day course of ophthalmic antimicrobials to their patients. In the control VDCs, FCHVs did not provide this intervention. Participants were not masked given the nature of the intervention. Both groups were followed up for 3 years for photographic evidence of corneal ulceration. The primary outcome was the incidence of corneal ulceration, determined by masked assessment of corneal photographs. The analysis was by intention to treat. This trial is registered with ClinicalTrials.gov, NCT01969786.FindingsWe assessed 112 VDCs, of which 24 were enrolled. The study was performed between Feb 4, 2014, and Oct 20, 2017. 12 VDCs were randomly assigned to the intervention group and 12 to the control group. 252 539 individuals were included in the study (130 579 in the intervention group and 121 960 in the control group). FCHVs diagnosed and provided antimicrobials for 4777 corneal abrasions. The census identified 289 corneal ulcers among 246 893 person-years in the intervention group (incidence 1·21 cases [95% CI 0·85-1·74] per 1000 person-years) and 262 corneal ulcers among 239 170 person-years in the control group (incidence 1·18 cases [0·82-1·70] per 1000 person-years; incidence rate ratio 1·03 [95% CI 0·63-1·67]; p=0·93). Medication allergy was self-reported in 0·2% of participants.InterpretationWe did not detect a reduction in the incidence of corneal ulceration during the first 3 years of a community-based corneal ulcer prevention programme. Further study might be warranted in more rural areas where basic eye care facilities are not available.FundingNational Eye Institute