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Controlled Clinical Trial
. 2012 May 15;185(10):1104-9.
doi: 10.1164/rccm.201107-1190OC. Epub 2012 Feb 9.

Surgical face masks worn by patients with multidrug-resistant tuberculosis: impact on infectivity of air on a hospital ward

Ashwin S Dharmadhikari  1 , Matsie Mphahlele, Anton Stoltz, Kobus Venter, Rirhandzu Mathebula, Thabiso Masotla, Willem Lubbe, Marcello Pagano, Melvin First, Paul A Jensen, Martie van der Walt, Edward A Nardell
Affiliations
Controlled Clinical Trial

Surgical face masks worn by patients with multidrug-resistant tuberculosis: impact on infectivity of air on a hospital ward

Ashwin S Dharmadhikari et al. Am J Respir Crit Care Med. .

Abstract

Rationale: Drug-resistant tuberculosis transmission in hospitals threatens staff and patient health. Surgical face masks used by patients with tuberculosis (TB) are believed to reduce transmission but have not been rigorously tested.

Objectives: We sought to quantify the efficacy of surgical face masks when worn by patients with multidrug-resistant TB (MDR-TB).

Methods: Over 3 months, 17 patients with pulmonary MDR-TB occupied an MDR-TB ward in South Africa and wore face masks on alternate days. Ward air was exhausted to two identical chambers, each housing 90 pathogen-free guinea pigs that breathed ward air either when patients wore surgical face masks (intervention group) or when patients did not wear masks (control group). Efficacy was based on differences in guinea pig infections in each chamber.

Measurements and main results: Sixty-nine of 90 control guinea pigs (76.6%; 95% confidence interval [CI], 68-85%) became infected, compared with 36 of 90 intervention guinea pigs (40%; 95% CI, 31-51%), representing a 56% (95% CI, 33-70.5%) decreased risk of TB transmission when patients used masks.

Conclusions: Surgical face masks on patients with MDR-TB significantly reduced transmission and offer an adjunct measure for reducing TB transmission from infectious patients.

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Figures

Figure 1.
Figure 1.
Diagram of AIR facility and exhaust system. Guinea pigs receive and breathe ward air for 12-hour periods on either (A) intervention (masks on), or (B) control (masks off) days. On days when a chamber does not receive ward air, its air comes directly from a central ventilation source (not shown). AIR = airborne infections research. GP = guinea pigs.
Figure 2.
Figure 2.
Picture of ear-loop face masks used in study.
Figure 3.
Figure 3.
Kaplan-Meier graph of guinea pig infections. Intervention group (blue line) represents guinea pigs sampling ward air when masks were worn by patients. Control group (red line) represents guinea pigs sampling ward air when masks were not worn by patients. The dashed lines denote the 95% confidence intervals for each line. X-axis shows timing of each monthly tuberculin skin test. Y-axis shows the cumulative proportion of infected guinea pigs at each testing interval.
See this image and copyright information in PMC

Comment in

  • Behind the mask: overdue evidence.
    Fennelly KP, Hosford JL. Fennelly KP, et al. Am J Respir Crit Care Med. 2012 May 15;185(10):1041-3. doi: 10.1164/rccm.201203-0548ED. Am J Respir Crit Care Med. 2012. PMID: 22589311 No abstract available.

References

    1. World Health Organization WHO report 2009 global tuberculosis control: epidemiology, strategy, financing. Geneva, Switzerland: World Health Organization; 2009
    1. World Health Organization WHO report 2010: multidrug and extensively drug-resistant TB (M/XDR-TB): 2010 global report on surveillance and response [Internet; accessed 2011 Jun 2]. Available from: http://www.Who.Int/tb/publications/2010/en/index.Html
    1. Gandhi NR, Moll A, Sturm AW, Pawinski R, Govender T, Lalloo U, Zeller K, Andrews J, Friedland G. Extensively drug-resistant tuberculosis as a cause of death in patients co-infected with tuberculosis and HIV in a rural area of South Africa. Lancet 2006;368:1575–1580 - PubMed
    1. O'Donnell MR, Jarand J, Loveday M, Padayatchi N, Zelnick J, Werner L, Naidoo K, Master I, Osburn G, Kvasnovsky C, et al. High incidence of hospital admissions with multidrug-resistant and extensively drug-resistant tuberculosis among South African health care workers. Ann Intern Med 2010;153:516–522 - PMC - PubMed
    1. Gelmanova IY, Keshavjee S, Golubchikova VT, Berezina VI, Strelis AK, Yanova GV, Atwood S, Murray M. Barriers to successful tuberculosis treatment in Tomsk, Russian Federation: non-adherence, default and the acquisition of multidrug resistance. Bull World Health Organ 2007;85:703–711 - PMC - PubMed

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