Dr Kubjane with her supervisor, Associate Professor Leigh Johnson
Supported by UCT Fogarty HIV-associated TB Training Program and other training programs
Supervisors: Associate Professor Leigh Johnson and Professor Andrew Boulle
Centre for Infectious Disease Epidemiology Research in School of Public Health at UCT
Mmamapudi Kubjane’s PhD, which was funded by Fogarty and other training programmes, focused on modelling TB and the effect of HIV on TB in South Africa. This involved extending an existing computer model of HIV in South Africa (the Thembisa model), extending the model to include TB, and calibrating the model to match TB programme data (recorded numbers of people diagnosed and treated for TB), recorded death statistics, TB prevalence data from national surveys and data on HIV prevalence in people receiving TB treatment. In the first paper from her PhD (published in 2022 in the International Journal of Infectious Diseases), she used the model to describe the evolution of the TB epidemic in South Africa up to 2019, including the effect of HIV. She also used the model to assess which TB and HIV interventions in South Africa have had the greatest impact on TB incidence: the scale-up of antiretroviral treatment (ART) and increased frequency of TB screening were both found to have had a major impact, while other interventions (such as directly observed treatment, isoniazid preventive therapy and the transition to GeneXpert testing) had only modest impacts.
The second paper of Mmamapudi’s PhD aimed to explain why TB incidence and TB mortality are so much higher in South African men than in South African women, despite HIV prevalence being much higher in women than in men. This involved running the model under different scenarios, to identify the relative importance of different variables in driving the sex differences. The analysis, published recently in Scientific Reports, suggests that much of the male-female difference can be attributed to the higher prevalence in men of smoking and alcohol use, both of which are major TB risk factors. In addition, men have lower rates of health seeking, which partly explains their higher TB mortality. Their lower rates of HIV testing and ART uptake (relative to women) also explain why HIV has more of an impact on TB in men than might otherwise be expected. Mmamapudi continues to work on using the model to assess the potential impact of future changes to TB programmes in South Africa (the third paper from her PhD), and is now working as part of a team of health economists to assess the cost-effectiveness and budget impact of different TB interventions.
Mmamapudi Kubjane, Muhammad Osman, Andrew Boulle, Leigh F. Johnson
Int J Infect Dis. 2022 Sep; 122: 811–819. doi: 10.1016/j.ijid.2022.07.047
Kubjane M, Cornell M, Osman M, Boulle A, Johnson LF. Sci Rep. 2023 Jun 10;13(1):9487. doi: 10.1038/s41598-023-36432-6. PMID: 37301904
View her Interview on eNCA on the reasons for the higher incidence of TB among men: