Measuring ventilation and modelling M. Tuberculosis transmission in indoor congregate settings, rural KwaZulu-Natal

J. G. Taylor*, T. A. Yates, M. Mthethwa, F. Tanser, Ibrahim Abubakar, H. Altamirano

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

13 Citations (Scopus)

Abstract

SETTING: Molecular epidemiology suggests that most Mycobacterium tuberculosis transmission in high-burden settings occurs outside the home. OBJECTIVE: To estimate the risk of M. tuberculosis transmission inside public buildings in a high TB burden community in KwaZulu-Natal, South Africa. DESIGN: Carbon dioxide (CO2) sensors were placed inside eight public buildings. Measurements were used with observations of occupancy to estimate infection risk using an adaptation of the Wells-Riley equation. Ventilation modelling using CONTAM was used to examine the impact of low-cost retrofits on transmission in a health clinic. RESULTS: Measurements indicate that infection risk in the church, classroom and clinic waiting room would be high with typical ventilation, occupancy levels and visit durations. For example, we estimated that health care workers in a clinic waiting room had a 16.9-24.5% annual risk of M. tuberculosis infection. Modelling results indicate that the simple addition of two new windows allowing for cross-ventilation, at a cost of US$330, would reduce the annual risk to health care workers by 57%. CONCLUSIONS: Results indicate that public buildings in this community have a range of ventilation and occupancy characteristics that may influence transmission risks. Simple retrofits may result in dramatic reductions in M. tuberculosis transmission, and intervention studies should therefore be considered.

Original languageEnglish
Pages (from-to)1155-1161 and iv
JournalInternational Journal of Tuberculosis and Lung Disease
Volume20
Issue number9
DOIs
Publication statusPublished - 1 Sep 2016
Externally publishedYes

Bibliographical note

Funding Information:
This project was funded via the University College London Grand Challenges Global Health Small Grant Scheme. TAY is in receipt of a PhD studentship from the UK Medical Research Council (MRC) (London, UK; MR/K50077X/1). FT was supported by South African MRC Flagship, Pretoria, South Africa (MRC-RFA-UFSP-01-2013/UKZN HIVEPI) and National Institutes of Health, Bethesda, MD, USA (R01 HD084233) grants as well as a UK Academy of Medical Sciences Newton Advanced Fellowship (NA150161). IA received funding from the MRC, National Institute for Health Research (London, UK), Public Health England (London) and the Wellcome Trust (London, UK). We thank P Mdletshe and the buildings' custodians for their assistance.

Publisher Copyright:
© 2016 Taylor et al.

Keywords

  • Infection control
  • South Africa
  • Wells-Riley equation

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