Doctoral Degrees (Epidemiology and Biostatistics)

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Browsing Doctoral Degrees (Epidemiology and Biostatistics) by browse.metadata.advisor "Uthman, Olalekan A."

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    Understanding the relationship between vaccination, vaccine-preventable diseases, and HIV infection among sub-Saharan African children
    (Stellenbosch : Stellenbosch University, 2019-04) Adetokunboh, Olatunji Oluseyi; Wiysonge, Charles S.; Uthman, Olalekan A.; Stellenbosch University. Faculty of Medicine and Health Sciences. Dept. of Global Health. Epidemiology and Biostatistics.
    ENGLISH SUMMARY : Numerous care and treatment guidelines pinpoint vaccination as a crucial preventive strategy for HIV-infected patients, but data regarding these vaccines among children living with HIV are still very scanty. There are knowledge gaps concerning the understanding of the mediators of vaccine protection, adverse effects and fundamental aspects of the epidemiology of various vaccine-preventable diseases. Likewise, there is also limited information on the determinants of vaccine non-uptake within the HIV-infected population, and on the association between maternal HIV status and the vaccination status of her HIV-exposed child. Further synthesis of all available evidence is required to provide reliable and easily accessible information for decision-makers and healthcare workers. We completed evidence synthesis of existing studies and secondary analyses of existing data sets using different research methods such as systematic review, meta-analysis, meta-regression and multivariable logistic regression models. We found that the burden of vaccine-preventable diseases is still high among HIV-infected and HIV-exposed children in sub-Saharan Africa. Several routine vaccines show possibilities for direct and indirect protection against various vaccine-preventable diseases among HIV-infected and HIV-exposed children. However, HIV-infected children are less likely to be protected against vaccine-preventable diseases when compared to non-exposed children. There is no significant difference in the uptake of the full series of three doses of diphtheria-tetanus-pertussis containing vaccines (DTP3) among infants of HIV-infected mothers and those of uninfected mothers in sub-Saharan Africa. Vaccination coverage for both HIV-exposed children and non-exposed children is still sub-optimal. Furthermore, individual and contextual factors such as maternal age, educational level, unemployment, and adult literacy level contributed significantly to non-uptake of DTP3 among the children of HIV-infected women across sub-Saharan Africa. The symptoms of acute respiratory infections show no statistical difference in the overall estimates between the children of HIV-infected mothers who were vaccinated with DTP3 and the ones who were not vaccinated. The data for episodes of diarrhoea were pooled together with resultant nil significant difference in the overall estimates between the children of HIV-infected mothers who were vaccinated with DTP3 and those not vaccinated. Many African countries also recorded high rates of respiratory infections and diarrhoeal diseases among both HIV-exposed and unexposed children. Residency in communities with high unemployment was an independent predictor of acute respiratory infections among immunised and HIV-exposed children while those born to women aged 15-24 or 25-34 years old were significantly more likely to develop diarrhoeal diseases. There is a need to address sub-optimal uptake of vaccines among HIV-exposed and non-exposed children. Epidemiological studies on vaccine-preventable diseases and the development of more efficacious vaccines are required for vaccine-preventable diseases studies with respect to HIV-infected and HIV-exposed uninfected children. The findings of this research would be useful in advocating for a more equitable share of healthcare resources especially for preventive services such as vaccination of both HIV-exposed and non-exposed children with subsequent reduction in the burden of vaccine-preventable diseases.
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    Using quality improvement approach to address missed opportunities for vaccination in Kano Metropolis, Nigeria
    (Stellenbosch : Stellenbosch University, 2019-12) Adamu, Abdu Abdullahi; Wiysonge, Charles S.; Uthman, Olalekan A.; Gadanya, Muktar A.; Stellenbosch University. Faculty of Medicine and Health Sciences. Dept. of Family and Emergency Medicine. Family Medicine and Primary Care.
    ENGLISH SUMMARY : Background Strategies to reduce missed opportunities for vaccination (MOV) can potentially increase immunization coverage in health facilities and invariably improve immunization coverage at the district and national level. Yet, there is a dearth of synthesized literature on MOV in Africa, despite being the region with the lowest immunization coverage globally. Furthermore, the use of quality improvement (QI) in health facilities to rapidly address health system problems is growing, but evidence of its use in the immunization sub-system to reduce MOV is scarce. Moreover, it is unclear how the QI approach can be applied in a low resource, low immunization coverage setting like Kano, Nigeria. Therefore in this project, empirical evidence on the burden and dynamics of MOV in Africa was generated as well as the extent to which practitioners in healthcare facilities have used QI to address it. This was followed by the implementation and evaluation of a QI programme to reduce MOV in Nassarawa Local Government Area, Kano State, Nigeria. Methodology A combination of methods including systematic review, scoping review, multilevel modelling, qualitative inquiry, time series, and mixed methods were used. Result The first component of the first phase, a systematic review, revealed that MOV is common among children aged 0 – 23 months who made contact with health facilities in Africa, with a pooled prevalence of 27.26%. However, only 20 MOV assessments from 14 African countries were found. The reasons for MOV were multifactorial and complex because they were interrelated and interdependent. The second component of the first phase, a scoping review, revealed that evidence on the use of QI to reduce MOV and improve immunization coverage in health facilities exists. However, the QI interventions that were found were all implemented in the United States. Plan-do-study-act (PDSA) cycles were the most commonly used models. In these QI programmes, practitioners used multiple change ideas simultaneously. The change ideas were client-related, health worker-related, and cross-cutting health system-related change ideas. The second phase was the pre-implementation period of a QI programme in Kano, Nigeria. The first component of the second phase, a cross sectional study, revealed an MOV prevalence of 36.15% among children aged 0 – 23 months who visited PHC facilities in Nassarawa Local Government Area (LGA) of Kano, Nigeria. MOV was more likely to occur among children who were accompanying a caregiver to the health facility and failure to offer vaccination on the day of clinic visit. In the second component of this phase, a qualitative study based on the lived experiences of caregivers, showed that non-screening of immunization history, refusal to offer vaccination, husband’s refusal and fear of side effects were responsible for MOV. In the third phase, locally relevant change ideas were implemented in five PHC facilities in Nassarawa LGA to address the identified factors. In the first component of the third phase, frontline health workers in these facilities systematically selected and implemented change ideas in two plan-do-study-act (PDSA) cycles that were four weeks apart. Using p-charts, reduction in proportion of MOV per day was seen in two facilities at the sixth week following implementation of the PDSA cycles. Then, an evaluation of the implementation context revealed that several facilitators and barriers influenced the implementation of the QI programme. Conclusion This study confirmed that MOV is a common immunization problem in Kano, like other settings in Africa. A bottom-up QI approach to address MOV, that is led by health workers in facilities, is feasible in this setting. However, rapid assessment of implementation context should be built into the QI process.