Modeling the impact of control measures on tuberculosis infection in senior care facilities

Tuberculosis (TB) is among the top ten causes of death worldwide. The impacts of potential control measures on TB infection in senior care facilities are poorly understood in Taiwan region. The purpose of this paper was to assess the impacts of potential control strategies for reducing the risk for TB infection among elderly in senior care facilities and to provide the suggestions for sound TB infection control measures that should be implemented in all senior care facilities with aged people suspected of having infectious TB. We proposed an integrated-level mathematical model, incorporating the TB transmission dynamics, the Wells-Riley mathematical equation, and the competing-risks model to quantify the potential spread of TB bacilli in senior care facilities. We found that individuals living in hospital-based nursing homes had much higher exposure to TB than those in long-term and domiciliary care facilities. We showed that the proposed combinations of engineering control measures (e.g., ventilation and ultraviolet germicidal irradiation) with personal protection (e.g., surgical mask) guarantee the provision of a reliable control strategy to decrease the transmission potential and spread rate of TB bacilli aerosols in senior care facilities in that the efficacies range from 45 to 90%. The introduction of appropriate TB transmission control measures may decrease TB annual incidence in senior care facilities by as much as 76-90% of tuberculin skin test (TST) conversion. Our study implicated that sound TB infection control measures, including diagnosis and prompt treatment of infectious cases should be prioritized.