Effect of ventilation improvement during a tuberculosis outbreak in underventilated university buildings
Journal
Indoor Air
Journal Volume
30
Journal Issue
3
Pages
422-432
Date Issued
2020
Author(s)
Abstract
The role of ventilation in preventing tuberculosis (TB) transmission has been widely proposed in infection control guidance. However, conclusive evidence is lacking. Modeling suggested the threshold of ventilation rate to reduce effective reproductive ratio (ratio between new secondary infectious cases and source cases) of TB to below 1 is corresponding to a carbon dioxide (CO2) level of 1000?parts?per?million (ppm). Here, we measured the effect of improving ventilation rate on a TB outbreak involving 27?TB cases and 1665 contacts in underventilated university buildings. Ventilation engineering decreased the maximum CO2 levels from 3204?±?50?ppm to 591-603?ppm. Thereafter, the secondary attack rate of new contacts in university dropped to zero (mean follow-up duration: 5.9?years). Exposure to source TB cases under CO2 >1000?ppm indoor environment was a significant risk factor for contacts to become new infectious TB cases (P?<.001). After adjusting for effects of contact investigation and latent TB infection treatment, improving ventilation rate to levels with CO2 <1000?ppm was independently associated with a 97% decrease (95% CI: 50%-99.9%) in the incidence of TB among contacts. These results show that maintaining adequate indoor ventilation could be a highly effective strategy for controlling TB outbreaks. ? 2019 The Authors. Indoor Air published by John Wiley & Sons Ltd
SDGs
Other Subjects
adult; air conditioning; epidemic; female; human; male; tuberculosis; university; Adult; Disease Outbreaks; Female; Humans; Male; Tuberculosis; Universities; Ventilation
Publisher
Blackwell Munksgaard
Type
journal article