South Africa is one of six countries worldwide that has the highest national burden of tuberculosis (TB) and the largest number of HIV-infected people in the world. HIV infection, Mycobacterium tuberculosis (M.tb) infection and TB disease is most common during a woman’s reproductive age, particularly in South African women. HIV co-infection increases the risk of TB disease either by facilitating reactivation of a latent TB infection or by favouring the progression of a recently acquired TB infection towards active disease in HIV-infected patients. Globally, HIV-TB co-infected adults are 19 times more likely to develop TB disease than HIV-uninfected adults, in the absence of preventive therapy. In South Africa 61% of TB cases are reported to be HIV-infected. HIV-infected pregnant women with latent TB infection are more likely to progress to active TB disease and women in the early postpartum period are twice as likely to develop TB as non-pregnant women, usually at 3 months post-delivery. More pregnant women die from TB disease than from any other pregnancy or childbirth related causes, particularly in South Africa. This risk is greater in HIV-infected, pregnant women, who account for 29.7% of pregnant women attending public antenatal clinic services in South Africa. Infants of pregnant women with TB have increased risks of mortality and morbidity compared to infants of women without TB, and these risks are even higher in pregnant women co-infected with HIV and TB. The risk of M.tb exposure, infection and TB disease in HIV-exposed, uninfected infants is high. An analysis is presented on the relationships between sociodemographic and clinical risk factors and M.tb infection and TB disease in HIVinfected mothers and HIV-exposed infants examined in the setting of an infant TB vaccine clinical trial. Prevalence of maternal M.tb infection and the incidence rate of maternal TB disease and infant M.tb infection and TB disease in this cohort is also investigated. The protocol (Part A) outlines the study design and the methodology of the research for this sub-analysis. The literature review (Part B) provides an overview of recent and current literature on the prevalence and incidence rate of M.tb infection and TB disease in HIV-infected pregnant and post-partum women and their HIV-exposed infants in resource-limited settings, particularly in sub-Saharan Africa and specifically in South Africa. Literature on the risk factors associated with the exposure and progression to M.tb infection and TB disease in these susceptible populations is described. The results of the sub- analysis are presented as a manuscript (Part C). The main findings are the incidence rate of maternal TB was 1.36/100 person-years and incidence rate of infant M.tb infection and TB was 2.47 and 3.62/100 personyears respectively. Maternal CD4 count >350 cells/mm³ was strongly associated with QFT positivity that may have affected the estimate of maternal M.tb infection. Infant M.tb infection was driven by new household TB contact(s) as was infant TB disease in addition to higher QFT values (IU/ml) and maternal smoking. Determining which pregnant or postpartum HIV-infected women and their infants are at the highest risk of becoming M.tb infected and developing TB disease, by improving active TB screening of mother-infant pairs, could be an important public health means to reducing the burden of disease and death caused by TB, particularly in HIV endemic areas of South Africa where Prevention of Mother to Child Transmission coverage is greater than 95%.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:uct/oai:localhost:11427/29656 |
| Date | 19 February 2019 |
| Creators | Downing, Katrina Jo |
| Contributors | Hatherill, Mark, Davies, Mary-Ann |
| Publisher | University of Cape Town, Faculty of Health Sciences, South African Tuberculosis Vaccine Initiative (SATVI) |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Master Thesis, Masters, MPH |
| Format | application/pdf |
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