Hotspots, Households and Hospitals: Enhanced Drug-resistant Tuberculosis Case Finding in Namibia

Poor case management, pharmacokinetic variability and on-going transmission have fostered the drug-resistant tuberculosis (DR-TB) epidemic leading to a global estimated number of \>500,000 new multidrug resistant (MDR) TB cases per year, of which roughly 10% are extensively drug resistant (XDR). Namibia is a high TB burden country with an incidence rate of 446/100,000 in 2016; about 11,000 new cases per year. 3.9% of new cases and 8.7% of previously treated cases have MDR-TB. Whole genome sequencing (WGS) has recently been applied to interrogate the complete genetic code of Mycobacterium tuberculosis (Mtb) strains. WGS can be used to infer relationships between identified strains as well as determine genomic variations involved in resistance development. The specific aims of the H3TB study are to: (i) characterise the DR-TB epidemic, in terms of clinical, epidemiological, geospatial, social network and laboratory data, to identify transmission hotspots in three regions of Namibia, (ii) evaluate the feasibility of targeted case finding intervention strategies to improve DR-TB control in highly affected populations and (iii) develop a transmission model to investigate the potential impact of the case finding intervention strategies on DR-TB incidence in Namibia. A prospective surveillance study started in January 2020, which includes all DR-TB cases in Namibia, and which will nest H3TB. Data collection tools and other study implementation tools have been designed and implemented. The study team is working in close collaboration with the National Institute of Pathology, where all DR-TB cases from the country are registered, to ensure all possible cases are captured. This is important for the identification of transmission hotspots. After HREC and MOHSS approval, individuals with GeneXpert® MTB/RIF rifampicin-resistant samples and a positive Mtb culture from three regions in Namibia will be included in a transmission hotspot identification study. Preliminary data hav