Improving tuberculosis case detection through contact risk stratification by Xpert MTB/RIF Ultra and spatial parameters: Evaluation of an innovative active case finding strategy in Mozambique (Xpatial-TB)

Belén Saavedra; Dinis Nguenha; Laura de la Torre-Pérez; Edson Mambuque; Gustavo Tembe; Laura Oliveras; Matthew Rudd; Paulo Philimone; Benedita Jose; Juan Ignacio Garcia; Neide Gomes; Shilzia Munguambe; Helio Chiconela; Milton Nhanommbe; Santiago Izco; Sozinho Acacio; Alberto L García-Basteiro

doi:10.1371/journal.pgph.0002789

Improving tuberculosis case detection through contact risk stratification by Xpert MTB/RIF Ultra and spatial parameters: Evaluation of an innovative active case finding strategy in Mozambique (Xpatial-TB)

PLOS Glob Public Health. 2024 Feb 9;4(2):e0002789. doi: 10.1371/journal.pgph.0002789. eCollection 2024.

Authors

Belén Saavedra^{1

2}, Dinis Nguenha¹, Laura de la Torre-Pérez^{1

2}, Edson Mambuque¹, Gustavo Tembe¹, Laura Oliveras^{3

4}, Matthew Rudd⁵, Paulo Philimone¹, Benedita Jose⁶, Juan Ignacio Garcia⁷, Neide Gomes¹, Shilzia Munguambe¹, Helio Chiconela^{1

6}, Milton Nhanommbe¹, Santiago Izco⁸, Sozinho Acacio¹, Alberto L García-Basteiro^{1

2}

Affiliations

¹ Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique.
² ISGlobal, Hospital Clínic-Universitat de Barcelona, Barcelona, Spain.
³ Agència de Salut Pública de Barcelona, Barcelona, Catalonia, Spain.
⁴ Institut d'Investigació Biomèdica Sant Pau (IIB Sant Pau) Barcelona, Catalonia, Spain.
⁵ Department of Mathematics and Computer Science, The University of the South, Sewanee, Tennessee, United States of America.
⁶ National Tuberculosis Control Programme, Maputo, Mozambique.
⁷ Population Health Program Texas Biomedical Research Institute, San Antonio, Texas, United States of America.
⁸ STD/HIV/Aids and Tuberculosis department, Ministry of Health and Social Welfare, Malabo, Equatorial Guinea.

Abstract

Prompt diagnosis is critical for tuberculosis (TB) control, as it enables early treatment which in turn, reduces transmission and improves treatment outcomes. We investigated the impact on TB diagnosis of introducing Xpert Ultra as the frontline diagnostic test, combined with an innovative active-case finding (ACF) strategy (based on Xpert Ultra semi-quantitative results and spatial parameters), in a semi-rural district of Southern Mozambique. From January-December 2018 we recruited incident TB-cases (index cases, ICs) and their household contacts (HCs). Recruitment of close community contacts (CCs) depended on IC´s Xpert Ultra results, and the population density of their area. TB-contacts, either symptomatic or people living with HIV, were asked to provide a spot sputum for lab-testing. Trends on TB case notification were compared to the previous years and to those of two districts in the south of the Maputo province (control area), using an interrupted time series analysis with and without control (CITS/ITS). A total of 1010 TB ICs (37.1% laboratory-confirmed) were recruited; 3165 HCs and 4730 CCs were screened for TB. Eighty-nine additional TB cases were identified through the ACF intervention (52.8% laboratory-confirmed). The intervention increased by 8.2% all forms of TB cases detected in 2018. Xpert Ultra trace positive results accounted for a high proportion of laboratory confirmations in the ACF cohort (51.1% vs 13.7% of those passively diagnosed). The Number Needed to Screen to find a TB case differed widely among HCs (55) and CCs (153). During the intervention period, a reversal of the previous negative trend in lab-confirmed case notifications was observed in the district. However, the CITS model did not show any statistically significant difference compared to the control area. Paediatric population benefited the most from the ACF strategy and HCs screening seemed an effective intervention to find microbiological confirmed cases in early stages of the disease.

Copyright: © 2024 Saavedra et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Grants and funding

This study was funded by the Stop-TB Partnership, as part of the TB REACH programme: Supporting Innovation in Detection and Care for Tuberculosis (wave 5). We acknowledge support from the Spanish Ministry of Science, Innovation and Universities through the ‘Centro de Excelencia Severo Ochoa 2019–2023’. Programme (CEX2018-000806-S),and support from the Generalitat de Catalunya through the CERCA Programme (B.S, L.T.P and A.G.B). B.S received a pre-doctoral fellowship from the Secretariat of Universities and Research, Ministry of Enterprise and Knowledge of the Government of Catalonia and co-funded by European Social Fund (AGAUR). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.