Novel approach to estimate tuberculosis transmission in primary care clinics in sub-Saharan Africa: protocol of a prospective study

Kathrin Zürcher; Carl Morrow; Julien Riou; Marie Ballif; Anastasia Sideris Koch; Simon Bertschinger; Xin Liu; Manuja Sharma; Keren Middelkoop; Digby Warner; Robin Wood; Matthias Egger; Lukas Fenner

doi:10.1136/bmjopen-2019-036214

Novel approach to estimate tuberculosis transmission in primary care clinics in sub-Saharan Africa: protocol of a prospective study

BMJ Open. 2020 Aug 26;10(8):e036214. doi: 10.1136/bmjopen-2019-036214.

Authors

Kathrin Zürcher¹, Carl Morrow^{2

3}, Julien Riou¹, Marie Ballif¹, Anastasia Sideris Koch^{3

4}, Simon Bertschinger^{1

5}, Xin Liu⁶, Manuja Sharma⁶, Keren Middelkoop^{2

3}, Digby Warner^{3

4}, Robin Wood^{2

3}, Matthias Egger^{1

7

8}, Lukas Fenner⁹

Affiliations

¹ Institute of Social and Preventive Medicine (ISPM), University of Bern, Bern, Switzerland.
² Desmond Tutu HIV Centre, Institute of Infectious Disease and Molecular Medicine (IDM), University of Cape Town, Cape Town, South Africa.
³ Institute of Infectious Disease and Molecular Medicine and the Department of Medicine, University of Cape Town, Rondebosch, Western Cape, South Africa.
⁴ Molecular Mycobacteriology Research Unit, University of Cape Town, Rondebosch, Western Cape, South Africa.
⁵ Medical Informatics, Berne University of Applied Sciences, Bern, Switzerland.
⁶ Paul G. Allen School of Computer Science & Engineering, University of Washington, Seattle, Washington, USA.
⁷ Centre for Infectious Disease Epidemiology & Research, School of Public Health & Family Medicine, University of Cape Town, Rondebosch, Western Cape, South Africa.
⁸ Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK.
⁹ Institute of Social and Preventive Medicine (ISPM), University of Bern, Bern, Switzerland lukas.fenner@ispm.unibe.ch.

Abstract

Introduction: Tuberculosis (TB) transmission is difficult to measure, and its drivers are not well understood. The effectiveness of infection control measures at healthcare clinics and the most appropriate intervention strategies to interrupt transmission are unclear. We propose a novel approach using clinical, environmental and position-tracking data to study the risk of TB transmission at primary care clinics in TB and HIV high burden settings in sub-Saharan Africa.

Methods and analysis: We describe a novel and rapid study design to assess risk factors for airborne TB transmission at primary care clinics in high-burden settings. The study protocol combines a range of different measurements. We will collect anonymous data on the number of patients, waiting times and patient movements using video sensors. Also, we will collect acoustic sound recordings to determine the frequency and intensity of coughing. Environmental data will include indoor carbon dioxide levels (CO₂ in parts per million) and relative humidity. We will also extract routinely collected clinical data from the clinic records. The number of Mycobacterium tuberculosis particles in the air will be ascertained from dried filter units using highly sensitive digital droplet PCR. We will calculate rebreathed air volume based on people density and CO₂ levels and develop a mathematical model to estimate the risk of TB transmission. The mathematical model can then be used to estimate the effect of possible interventions such as separating patient flows or improving ventilation in reducing transmission. The feasibility of our approach was recently demonstrated in a pilot study in a primary care clinic in Cape Town, South Africa.

Ethics and dissemination: The study was approved by the University of Cape Town (HREC/REF no. 228/2019), the City of Cape Town (ID-8139) and the Ethics Committee of the Canton Bern (2019-02131), Switzerland. The results will be disseminated in international peer-reviewed journals.

Keywords: infectious diseases; primary care; public health; tuberculosis.

Publication types

Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't

MeSH terms

Humans
Pilot Projects
Primary Health Care
Prospective Studies
South Africa
Switzerland
Tuberculosis* / diagnosis
Tuberculosis* / epidemiology
Tuberculosis* / prevention & control

Grants and funding

U01 AI069924/AI/NIAID NIH HHS/United States