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Volume 3, Number 3—September 1997


Using a Mathematical Model to Evaluate the Efficacy of TB Control Measures

Laura Gammaitoni and Maria Clara NucciComments to Author 
Author affiliations: University of Perugia, Perugia, Italy

Main Article

Table 1

Nosocomial TB outbreaks involving health-care workers who performed high-risk procedures

Pulmonary ventilation
p(m3/min) Room volume
V(m3) No. of susceptible
persons S0
No. of uninfected
personsformula image
Exposure time
t (min) Infection rate
q (qpm) Disinfection rate
Bronchoscopy 10-2 200 13 3 150 6 1.26
Abscess irrigation 6 x 10-3a 200b 5 1 150b 38 6b
Autopsy 10-2 200b 4 0c 150b 94 11
Intubation 6 x 10-3a 3000 3 1 66 514 2.4d

aSurgical masks were adopted.
bEstimated value; actual data are not available
cWe assumed S=0.001≈0.
dIn the emergency department where this outbreak developed, 60% of the air was recirculated without filtration; we assumed an airflow rate of 6 ACH, obtaining an effective disinfection rate equal to 40% of 6 ACH.

Main Article