During the guideline development process, the Guideline Development Group identified important knowledge gaps that need to be closed through both primary and secondary research in order to better inform the adoption of current IPC practices and, potentially, of new practices.
The general research gaps listed below are to be prioritized for all IPC interventions:
- Individual effect of interventions: Most studies informing these guidelines evaluated the effect of composite measures. Consequently, accurate assessment of the effect of a single component of infection control practices was not possible. The Guideline Development Group suggested that further high-quality prospective research studies (e.g. employing randomized designs) be conducted to evaluate the effect of single interventions.
- Higher quality studies: Most of the research evidence informing these recommendations comprised uncontrolled before-and-after studies. This design is considered most useful in demonstrating the immediate impacts of short-term interventions, but is less valuable when evaluating longterm interventions, given that other temporal factors may obscure the effects of an intervention. Modelling studies may improve understanding of the likely effect and cost–effectiveness, if appropriately parameterized. Alternative study designs such as randomized controlled trials should be considered to minimize bias. Further experimental studies where outcomes are measured in animals may also provide useful evidence of the effect of selected interventions on transmission – a particular advantage of these studies being that individual IPC interventions may be studied one at a time.
- Cost–effectiveness: Limited evidence is available regarding the cost–effectiveness of IPC measures, other than treatment of TB disease. Information from cost– effectiveness research is required to organize IPC measures at all levels of care and other at-risk settings (e.g. congregate settings) in such a way that benefits can be optimized within available resource constraints, especially in resource-limited and high TB burden areas.
- Implementation science research: This form of research provides valuable insights into the feasibility and impact of guidelines in a local context. Countries are encouraged to apply implementation science methodologies to systematically evaluate the introduction of TB IPC standards at both national and subnational levels.
- Risk assessment settings: Further research is required to strengthen the understanding of the incidence of M. tuberculosis infection and TB disease, including its drug-resistant forms, among health workers and other high-risk populations.
The Guideline Development Group further identified various research priorities for individual interventions, as outlined below.
- Evaluation of different approaches to triage in general, including triage needs and specific priorities for individuals with comorbidities such as HIV and noncommunicable diseases (e.g. triage strategies in HIV facilities and in noncommunicable disease programmes).
- Evaluation of the appropriate duration of respiratory isolation necessary to minimize the risk of infection to others.
Rapid diagnosis and initiation of effective treatment
- Determination of the effect of treatment on the duration of infectiousness of TB patients.
- High-quality studies evaluating the effectiveness of surgical masks and other non-mask respiratory hygiene interventions in a clinical setting.
Upper-room Guv systems
- Direct research evidence, including programme data, on the effectiveness of upper-room GUV on outcomes that are important to patients and health workers.
- Further research on safe and effective upper-room GUV dosing by space volume (in cubic feet or metres) to guide implementation.
- Effect of different air exchange rates in mechanical ventilation systems on transmission of M. tuberculosis.
- Effect of mechanical ventilation modes on microclimate of mechanically ventilated settings.
- High-quality research evaluating the effect of portable room-air cleaners.
- Further research on ventilation parameters for portable room-air cleaners and target product profiles for these devices.
Respiratory protection programmes
- Evaluation of the duration of effectiveness of filtering particulate respirators.