{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"institution":[{"name":"medRxiv"}],"indexed":{"date-parts":[[2026,9,29]],"date-time":"2026-09-29T16:06:58Z","timestamp":1790698018709,"version":"4.1.0"},"posted":{"date-parts":[[2025,12,27]]},"group-title":"Public and Global Health","reference-count":30,"publisher":"openRxiv","license":[{"start":{"date-parts":[[2025,12,27]],"date-time":"2025-12-27T00:00:00Z","timestamp":1766793600000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"accepted":{"date-parts":[[2025,12,27]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                <jats:sec>\n                  <jats:title>Background<\/jats:title>\n                  <jats:p>\n                    Hospitals in high-burden tuberculosis (TB) settings are important sites of\n                    <jats:italic>Mycobacterium tuberculosis<\/jats:italic>\n                    (\n                    <jats:italic>Mtb)<\/jats:italic>\n                    transmission, yet the impact of infection prevention and control (IPC) measures targeting crowding is poorly understood. We assessed the effects of simple interventions to reduce spatial clustering and airborne transmission in a Zambian hospital.\n                  <\/jats:p>\n                <\/jats:sec>\n                <jats:sec>\n                  <jats:title>Methods and findings<\/jats:title>\n                  <jats:p>\n                    From June to August 2024, we prospectively collected clinical data on presumptive (symptom-based screening) and confirmed (Xpert-positive, chest X-ray) TB patients, indoor CO\n                    <jats:sub>2<\/jats:sub>\n                    levels, bioaerosol samples, and continuous person movements (optical sensors) in the hospital\u2019s main waiting hall. Airborne\n                    <jats:italic>Mtb<\/jats:italic>\n                    DNA was detected using hourly cyclonic bioaerosol sampling. Using a spatiotemporal Wells\u2013Riley model integrating ventilation, proximity between visitors, and movement patterns, we estimated\n                    <jats:italic>Mtb<\/jats:italic>\n                    transmission risk under routine conditions and during two IPC interventions: (1) an optimised waiting-area layout with physical distancing measures; and (2) an added one-way patient flow system.\n                  <\/jats:p>\n                  <jats:p>\n                    During 52 days, 668 presumptive and 45 confirmed TB patients visited the hospital, and 671 840 person movements were recorded. Despite excellent natural ventilation (median CO\n                    <jats:sub>2<\/jats:sub>\n                    455 ppm; 8.0 air changes per hour), airborne\n                    <jats:italic>Mtb<\/jats:italic>\n                    was detected on six days. The first intervention reduced spatial clustering by an estimated 24% (95% credible interval [CrI] 13\u201332) and the second by 13% (95% CrI 1\u201323). The interventions lowered\n                    <jats:italic>Mtb<\/jats:italic>\n                    transmission risk by an estimated 39% (95% CrI 29\u201348) and 21% (95% CrI 9\u201332), respectively. Over the four weeks of implementation, they collectively averted an estimated 16 (95% CrI 8\u201326) infections.\n                  <\/jats:p>\n                <\/jats:sec>\n                <jats:sec>\n                  <jats:title>Conclusions<\/jats:title>\n                  <jats:p>\n                    In this high-burden, well-ventilated hospital, short-range exposure remained a driver of airborne\n                    <jats:italic>Mtb<\/jats:italic>\n                    transmission. Simple, low-cost operational changes to reduce clustering substantially decreased proximity-driven transmission risk. Integrating proximity-focused strategies can meaningfully strengthen IPC in resource-limited healthcare settings.\n                  <\/jats:p>\n                <\/jats:sec>","DOI":"10.64898\/2025.12.24.25342956","type":"posted-content","created":{"date-parts":[[2025,12,28]],"date-time":"2025-12-28T01:05:13Z","timestamp":1766883913000},"source":"Crossref","is-referenced-by-count":1,"title":["Reducing spatial clustering to prevent tuberculosis transmission in a busy Zambian hospital: a modelling study based on person movements, environmental and clinical data"],"prefix":"10.64898","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-0138-6120","authenticated-orcid":false,"given":"Nicolas","family":"Banholzer","sequence":"first","affiliation":[{"name":"Institute of Social and Preventive Medicine, University of Bern, Bern, Switzerland"},{"name":"Section of Health Data Science and AI, Department of Public Health, University of Copenhagen, Copenhagen, Denmark"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Guy","family":"Muula","sequence":"additional","affiliation":[{"name":"Centre for Infectious Disease Research in Zambia (CIDRZ), Lusaka, Zambia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Fiona","family":"Mureithi","sequence":"additional","affiliation":[{"name":"Centre for Infectious Disease Research in Zambia (CIDRZ), Lusaka, Zambia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Esau","family":"Banda","sequence":"additional","affiliation":[{"name":"Centre for Infectious Disease Research in Zambia (CIDRZ), Lusaka, Zambia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Pascal","family":"Bittel","sequence":"additional","affiliation":[{"name":"Institute for Infectious Diseases, University of Bern, Bern, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lavinia","family":"Furrer","sequence":"additional","affiliation":[{"name":"Institute for Infectious Diseases, University of Bern, Bern, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"David","family":"Kronthaler","sequence":"additional","affiliation":[{"name":"Institute of Social and Preventive Medicine, University of Bern, Bern, Switzerland"},{"name":"Department of Psychology, University of Zurich, Zurich, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0008-3207-8052","authenticated-orcid":false,"given":"Remo","family":"Schmutz","sequence":"additional","affiliation":[{"name":"Institute of Social and Preventive Medicine, University of Bern, Bern, Switzerland"},{"name":"Division of Clinical Epidemiology, Department of Clinical Research, University of Basel, Basel, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Matthias","family":"Egger","sequence":"additional","affiliation":[{"name":"Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Switzerland"},{"name":"Population health Sciences, Bristol Medical School, University of Bristol, Bristol, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Carolyn","family":"Bolton","sequence":"additional","affiliation":[{"name":"Centre for Infectious Disease Research in Zambia (CIDRZ), Lusaka, Zambia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3309-4835","authenticated-orcid":false,"given":"Lukas","family":"Fenner","sequence":"additional","affiliation":[{"name":"Institute of Social and Preventive Medicine, University of Bern, Bern, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"54368","reference":[{"key":"2025123102251864000_2025.12.24.25342956v1.1","unstructured":"World Health Organization. Global Tuberculosis Report 2024. https:\/\/www.who.int\/teams\/global-programme-on-tuberculosis-and-lung-health\/tb-reports\/global-tuberculosis-report-2024 (accessed Oct 8, 2025)."},{"key":"2025123102251864000_2025.12.24.25342956v1.2","doi-asserted-by":"publisher","DOI":"10.1016\/S1473&ndash;3099(15)00499&ndash;5"},{"key":"2025123102251864000_2025.12.24.25342956v1.3","doi-asserted-by":"publisher","DOI":"10.1136\/bmjgh-2021-007124"},{"key":"2025123102251864000_2025.12.24.25342956v1.4","doi-asserted-by":"crossref","first-page":"e007136","DOI":"10.1136\/bmjgh-2021-007136","article-title":"Estimating the contribution of transmission in primary healthcare clinics to community-wide TB disease incidence, and the impact of infection prevention and control interventions, in KwaZulu-Natal","volume":"7","year":"2022","journal-title":"South Africa. BMJ Glob Health"},{"key":"2025123102251864000_2025.12.24.25342956v1.5","doi-asserted-by":"publisher","DOI":"10.1164\/rccm.201107-1190OC"},{"key":"2025123102251864000_2025.12.24.25342956v1.6","doi-asserted-by":"crossref","first-page":"107921","DOI":"10.1016\/j.ijid.2025.107921","article-title":"Infection prevention and control measures during the COVID-19 pandemic and airborne tuberculosis transmission during primary care visits in South Africa","volume":"156","year":"2025","journal-title":"Int J Infect Dis"},{"key":"2025123102251864000_2025.12.24.25342956v1.7","doi-asserted-by":"crossref","first-page":"e1012823","DOI":"10.1371\/journal.pcbi.1012823","article-title":"Estimating Mycobacterium tuberculosis transmission in a South African clinic: Spatiotemporal model based on person movements","volume":"21","year":"2025","journal-title":"PLOS Comput Biol"},{"key":"2025123102251864000_2025.12.24.25342956v1.8","doi-asserted-by":"publisher","DOI":"10.1093\/oxfordjournals.aje.a112560"},{"key":"2025123102251864000_2025.12.24.25342956v1.9","doi-asserted-by":"publisher","DOI":"10.1034\/j.1600-0668.2003.00189.x"},{"key":"2025123102251864000_2025.12.24.25342956v1.10","doi-asserted-by":"crossref","first-page":"1642","DOI":"10.1093\/infdis\/jiab534","article-title":"Estimating tuberculosis transmission risks in a primary care clinic in South Africa: Modeling of environmental and clinical data","volume":"225","year":"2022","journal-title":"J Infect Dis"},{"key":"2025123102251864000_2025.12.24.25342956v1.11","unstructured":"World Health Organization. Definitions and reporting framework for tuberculosis \u2013 2013 revision: updated December 2014 and January 2020. 2014 https:\/\/www.who.int\/publications\/i\/item\/9789241505345 (accessed Oct 17, 2025)."},{"key":"2025123102251864000_2025.12.24.25342956v1.12","doi-asserted-by":"crossref","first-page":"110731","DOI":"10.1016\/j.isci.2024.110731","article-title":"Persistent Mycobacterium tuberculosis bioaerosol release in a tuberculosis-endemic setting","volume":"27","year":"2024","journal-title":"iScience"},{"key":"2025123102251864000_2025.12.24.25342956v1.13","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.2314813121"},{"key":"2025123102251864000_2025.12.24.25342956v1.14","doi-asserted-by":"crossref","first-page":"145","DOI":"10.3390\/ijerph14020145","article-title":"Review and extension of CO2-based methods to determine ventilation rates with application to school classrooms","volume":"14","year":"2017","journal-title":"Int J Env Res Public Health"},{"key":"2025123102251864000_2025.12.24.25342956v1.15","doi-asserted-by":"publisher","DOI":"10.1371\/journal.pmed.1004226"},{"key":"2025123102251864000_2025.12.24.25342956v1.16","doi-asserted-by":"publisher","DOI":"10.1016\/S1473-3099(17)30691-6"},{"key":"2025123102251864000_2025.12.24.25342956v1.17","doi-asserted-by":"publisher","DOI":"10.1371\/journal.pmed.0050188"},{"key":"2025123102251864000_2025.12.24.25342956v1.18","doi-asserted-by":"crossref","first-page":"1349","DOI":"10.1086\/515397","article-title":"The detection of airborne transmission of Tuberculosis from HIV-infected patients, using an in vivo air sampling model","volume":"44","year":"2007","journal-title":"Clin Infect Dis Off Publ Infect Dis Soc Am"},{"key":"2025123102251864000_2025.12.24.25342956v1.19","unstructured":"US Centers for Disease Control and Prevention. Taking Steps for Cleaner Air for Respiratory Virus Prevention. Respir. Illnesses. 2025. https:\/\/www.cdc.gov\/respiratory-viruses\/prevention\/air-quality.html (accessed Oct 14, 2025)."},{"key":"2025123102251864000_2025.12.24.25342956v1.20","unstructured":"The Lancet COVID-19 Commission Task Force on Safe Work, Safe School, and Safe Travel. Proposed non-infectious air delivery rates (NADR) for reducing exposure to airborne respiratory infectious diseases. 2022 files.unsdsn.org\/Proposed%20Non-infectious%20Air%20Delivery%20Rates%20%28NADR%29%20for%20Reducing%20Exposure%20to%20Airborne%20Respiratory%20Infectious%20Diseases.pdf?utm_source=chatgpt.com (accessed Oct 14, 2025)."},{"key":"2025123102251864000_2025.12.24.25342956v1.21","doi-asserted-by":"crossref","first-page":"e0000603","DOI":"10.1371\/journal.pgph.0000603","article-title":"Direct estimates of absolute ventilation and estimated Mycobacterium tuberculosis transmission risk in clinics in South Africa","volume":"2","year":"2022","journal-title":"PLOS Glob Public Health"},{"key":"2025123102251864000_2025.12.24.25342956v1.22","doi-asserted-by":"publisher","DOI":"10.1186\/s12879-019-3717-9"},{"key":"2025123102251864000_2025.12.24.25342956v1.23","doi-asserted-by":"publisher","DOI":"10.1093\/oxfordjournals.aje.a117542"},{"key":"2025123102251864000_2025.12.24.25342956v1.24","doi-asserted-by":"crossref","first-page":"113752","DOI":"10.1016\/j.buildenv.2025.113752","article-title":"A rapid assessment method for airborne transmission risk distribution based on human behaviors","volume":"286","year":"2025","journal-title":"Build Environ"},{"key":"2025123102251864000_2025.12.24.25342956v1.25","doi-asserted-by":"crossref","first-page":"pgac223","DOI":"10.1093\/pnasnexus\/pgac223","article-title":"Risk assessment for long- and short-range airborne transmission of SARS-CoV-2, indoors and outdoors","volume":"1","year":"2022","journal-title":"PNAS Nexus"},{"key":"2025123102251864000_2025.12.24.25342956v1.26","doi-asserted-by":"publisher","DOI":"10.1111\/j.0272-4332.2004.00439.x"},{"key":"2025123102251864000_2025.12.24.25342956v1.27","doi-asserted-by":"publisher","DOI":"10.1056\/NEJM199604113341501"},{"key":"2025123102251864000_2025.12.24.25342956v1.28","doi-asserted-by":"publisher","DOI":"10.1093\/cid\/ciaa1057"},{"key":"2025123102251864000_2025.12.24.25342956v1.29","doi-asserted-by":"crossref","first-page":"1797","DOI":"10.1016\/S0140-6736(25)00555-0","article-title":"Asymptomatic tuberculosis: undetected and underestimated, but not unimportant","volume":"405","year":"2025","journal-title":"The Lancet"},{"key":"2025123102251864000_2025.12.24.25342956v1.30","doi-asserted-by":"publisher","DOI":"10.1016\/S1473-3099(10)70164-X"}],"container-title":[],"original-title":[],"link":[{"URL":"https:\/\/syndication.highwire.org\/content\/doi\/10.64898\/2025.12.24.25342956","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,12,31]],"date-time":"2025-12-31T10:25:25Z","timestamp":1767176725000},"score":1,"resource":{"primary":{"URL":"http:\/\/medrxiv.org\/lookup\/doi\/10.64898\/2025.12.24.25342956"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,12,27]]},"references-count":30,"URL":"https:\/\/doi.org\/10.64898\/2025.12.24.25342956","relation":{},"subject":[],"published":{"date-parts":[[2025,12,27]]},"subtype":"preprint"}}