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


OBJECTIVE
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.


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.
Division of Pulmonary and Critical Care Medicine, Division of Global Health Equity, Brigham and Women's Hospital, Harvard Medical School, 641 Huntington Avenue, Room 3A03, Boston, MA 02115, USA. adharmadhikari@partners.org
Ashwin S
AS
Dharmadhikari
Matsie
M
Mphahlele
Anton
A
Stoltz
Kobus
K
Venter
Rirhandzu
R
Mathebula
Thabiso
T
Masotla
Willem
W
Lubbe
Marcello
M
Pagano
Melvin
M
First
Paul A
PA
Jensen
Martie
M
van der Walt
Edward A
EA
Nardell
D000328:Adult; D000818:Animals; D005260:Female; D006168:Guinea Pigs; D006801:Humans; D017053:Infection Control / Q000295:instrumentation*; D017758:Infectious Disease Transmission, Patient-to-Professional / Q000517:prevention & control; D008297:Male; D008397:Masks; D008875:Middle Aged; D011446:Prospective Studies; D016896:Treatment Outcome; D018088:Tuberculosis, Multidrug-Resistant / Q000517:prevention & control* / Q000635:transmission; D014397:Tuberculosis, Pulmonary / Q000517:prevention & control* / Q000635:transmission