Evidence for the Use of Triage, Respiratory Isolation, and Effective Treatment to Reduce the Transmission of Mycobacterium Tuberculosis in Healthcare Settings: A Systematic Review

Modelling the effect of infection prevention and control measures on rate of Mycobacterium tuberculosis transmission to clinic attendees in primary health clinics in South Africa

BACKGROUND

Elevated rates of tuberculosis in healthcare workers demonstrate the high rate of Mycobacterium tuberculosis (Mtb) transmission in health facilities in high-burden settings. In the context of a project taking a whole systems approach to tuberculosis infection prevention and control (IPC), we aimed to evaluate the potential impact of conventional and novel IPC measures on Mtb transmission to patients and other clinic attendees.

METHODS

An individual-based model of patient movements through clinics, ventilation in waiting areas, and Mtb transmission was developed, and parameterised using empirical data from eight clinics in two provinces in South Africa. Seven interventions-codeveloped with health professionals and policy-makers-were simulated: (1) queue management systems with outdoor waiting areas, (2) ultraviolet germicidal irradiation (UVGI) systems, (3) appointment systems, (4) opening windows and doors, (5) surgical mask wearing by clinic attendees, (6) simple clinic retrofits and (7) increased coverage of long antiretroviral therapy prescriptions and community medicine collection points through the Central Chronic Medicine Dispensing and Distribution (CCMDD) service.

RESULTS

In the model, (1) outdoor waiting areas reduced the transmission to clinic attendees by 83% (IQR 76%-88%), (2) UVGI by 77% (IQR 64%-85%), (3) appointment systems by 62% (IQR 45%-75%), (4) opening windows and doors by 55% (IQR 25%-72%), (5) masks by 47% (IQR 42%-50%), (6) clinic retrofits by 45% (IQR 16%-64%) and (7) increasing the coverage of CCMDD by 22% (IQR 12%-32%).

CONCLUSIONS

The majority of the interventions achieved median reductions in the rate of transmission to clinic attendees of at least 45%, meaning that a range of highly effective intervention options are available, that can be tailored to the local context. Measures that are not traditionally considered to be IPC interventions, such as appointment systems, may be as effective as more traditional IPC measures, such as mask wearing.

Reducing the risk of tuberculosis transmission for HCWs in high incidence settings

Globally, tuberculosis (TB) is a leading cause of death from a single infectious agent. Healthcare workers (HCWs) are at increased risk of hospital-acquired TB infection due to persistent exposure to Mycobacterium tuberculosis (Mtb) in healthcare settings. The World Health Organization (WHO) has developed an international system of infection prevention and control (IPC) interventions to interrupt the cycle of nosocomial TB transmission. The guidelines on TB IPC have proposed a comprehensive hierarchy of three core practices, comprising: administrative controls, environmental controls, and personal respiratory protection. However, the implementation of most recommendations goes beyond minimal physical and organisational requirements and thus cannot be appropriately introduced in resource-constrained settings and areas of high TB incidence. In many low- and middle-income countries (LMICs) the lack of knowledge, expertise and practice on TB IPC is a major barrier to the implementation of essential interventions. HCWs often underestimate the risk of airborne Mtb dissemination during tidal breathing. The lack of required expertise and funding to design, install and maintain the environmental control systems can lead to inadequate dilution of infectious particles in the air, and in turn, increase the risk of TB dissemination. Insufficient supply of particulate respirators and lack of direction on the re-use of respiratory protection is associated with unsafe working practices and increased risk of TB transmission between patients and HCWs. Delayed diagnosis and initiation of treatment are commonly influenced by the effectiveness of healthcare systems to identify TB patients, and the availability of rapid molecular diagnostic tools. Failure to recognise resistance to first-line drugs contributes to the emergence of drug-resistant Mtb strains, including multidrug-resistant and extensively drug-resistant Mtb. Future guideline development must consider the social, economic, cultural and climatic conditions to ensure that recommended control measures can be implemented in not only high-income countries, but more importantly low-income, high TB burden settings. Urgent action and more ambitious investments are needed at both regional and national levels to get back on track to reach the global TB targets, especially in the context of the COVID-19 pandemic.

Context matters: Examining the factors impacting the implementation of tuberculosis infection prevention and control guidelines in health settings in seven high tuberculosis burden countries

BACKGROUND

Healthcare workers (HCWs) in high tuberculosis (TB) burden countries are at increased risk of TB infection due to increased exposures to TB patients and inadequate implementation of TB infection prevention and control (TB IPC) measures in health settings. While various guidelines on TB IPC exist, there is little understanding of the content of these guidelines, whether they are relevant to the context and are being appropriately implemented in low-and middle-income high TB burden countries. This study aimed to critically examine the implementation of TB IPC guidelines, along with factors impacting TB IPC implementation in health settings in seven high TB burden countries.

METHODS

The WHO 2009 and national level TB IPC guidelines and the published literature from seven TB high burden countries were reviewed and relevant information extracted. Eleven key-stakeholders from the case study countries were interviewed to elucidate further facilitators and barriers impacting TB IPC guidelines implementation.

RESULTS

Our study identified that all the study countries adopted the WHO 2009 guidelines with no or minimal modifications for the local context. Therefore, the subsequent translation of the TB IPC recommendations into practice has been limited and impaired in some settings. Poor infrastructure, inadequate space for isolation, lack of TB IPC training, limited supply of personal protective equipment, the discomfort of using N95 respirators, and a high number of TB patients were some of the factors impacting the implementation of TB IPC guidelines.

CONCLUSION

The implementation of TB IPC guidelines in all seven countries was limited. It was affected by the diverse context where each of the countries and each of the facilities had a different health infrastructure and TB disease burdens. The findings warrant re-assessment of the current context prevailing in these high TB burden countries and subsequent revisions of national guidelines based to account for local context and evidence.