Population-wide active case finding and prevention for tuberculosis and leprosy elimination in Kiribati: the PEARL study protocol.

INTRODUCTION: Population-wide interventions offer a pathway to tuberculosis (TB) and leprosy elimination, but 'real-world' implementation in a high-burden setting using a combined approach has not been demonstrated. This implementation study aims to demonstrate the feasibility and evaluate the effect of population-wide screening, treatment and prevention on TB and leprosy incidence rates, as well as TB transmission. METHODS AND ANALYSIS: A non-randomised 'screen-and-treat' intervention conducted in the Pacific atoll of South Tarawa, Kiribati. Households are enumerated and all residents ≥3 years, as well as children <3 years with recent household exposure to TB or leprosy, invited for screening. Participants are screened using tuberculin skin testing, signs and symptoms of TB or leprosy, digital chest X-ray with computer-aided detection and sputum testing (Xpert MTB/RIF Ultra). Those diagnosed with disease are referred to the National TB and Leprosy Programme for management. Participants with TB infection are offered TB preventive treatment and those without TB disease or infection, or leprosy, are offered leprosy prophylaxis. The primary study outcome is the difference in the annual TB case notification rate before and after the intervention; a similar outcome is included for leprosy. The effect on TB transmission will be measured by comparing the estimated annual risk of TB infection in primary school children before and after the intervention, as a co-primary outcome used for power calculations. Comparison of TB and leprosy case notification rates in South Tarawa (the intervention group) and the rest of Kiribati (the control group) before, during and after the intervention is a secondary outcome. ETHICS AND DISSEMINATION: Approval was obtained from the University of Sydney Human Research Ethics Committee (project no. 2021/127) and the Kiribati Ministry of Health and Medical Services (MHMS). Findings will be shared with the MHMS and local communities, published in peer-reviewed journals and presented at international conferences.

Impact of Laboratory Practice Changes on the Diagnosis of Tuberculosis with the Introduction of Xpert MTB/RIF in Kiribati.

The Republic of Kiribati, Central Pacific, has the largest tuberculosis epidemic in the region. There is a national tuberculosis control program, which has used smear microscopy for acid-fast bacilli as the main diagnostic tool for many years. In 2015, an Xpert MTB/RIF machine was procured and became functional within the tuberculosis hospital. The aim of this cross-sectional study, using routinely collected data, was to determine the effects of introducing Xpert MTB/RIF on laboratory smear microscopy practices and the pattern of registered tuberculosis cases. Between February 2015 and January 2016, there were 220 Xpert MTB/RIF assays performed with 6.4% errors and 15% detection of Mycobacterium tuberculosis: one patient showed rifampicin-resistance. One year before and after introducing Xpert MTB/RIF, the number of presumptive tuberculosis patients increased by 9% from 2,138 to 2,322. There were no changes in demographic characteristics, smear-positive results, or acid-fast bacilli grade between the two periods. The number of specimens cultured for Mycobacterium tuberculosis significantly declined from 638 to zero, with 76 positive MTB cultures before and none after introducing Xpert MTB/RIF. There was a significant change in the profile of registered tuberculosis cases with more children (34% versus 21%) and fewer bacteriologically-confirmed cases (29% versus 43%) - P < .001. Since the deployment of Xpert MTB/RIF in Kiribati, there have been a small number of assays performed and this has been associated with no adverse effects on smear microscopy, a stoppage in mycobacterial cultures, and a change in the types and categories of diagnosed tuberculosis.