Mburu, C; (2024) The utility of mathematical modelling of serological data in assessing the impact of vaccination programmes in Kenya. PhD thesis, London School of Hygiene & Tropical Medicine. DOI: https://doi.org/10.17037/PUBS.04673129
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Abstract
The concept of employing serosurveillance to assess the presence of pathogen-specific antibodies within populations and define the infectious disease landscape is gaining rapid momentum. This approach is increasingly recognized as a potent tool that can complement conventional case-based disease surveillance and routine vaccination coverage estimates, supplying a substantial amount of information to shape and guide immunisation programs. Despite its prevalence in high-income countries (HICs), it is still underutilised in low- and middle-income countries (LMICs). In this thesis, I have utilised a series of case studies in an LMIC setting across different pathogens to critically assess the added value of serosurveillance beyond vaccine coverage estimates and case-based surveillance data in enhancing our understanding and ability to control vaccine-preventable diseases (VPDs). Using age-stratified seroprevalence estimates spanning 2009 to 2021, encompassing measles, rubella, tetanus, diphtheria, pertussis, and Hepatitis B, I have demonstrated how serosurveys enhance situational awareness regarding the proportion of susceptible populations. I have also shown examples of how these estimates can inform revisions to existing programs like guiding targeted SIAs in the case of measles or assessing the need for booster doses in the cases of diphtheria and tetanus. Next, I have illustrated the synergistic utility of combining serosurveillance data, case surveillance data, and routine coverage data in evaluating the trade-offs among various intervention programs. In addition to emphasizing the importance optimising routine coverage timing and uptake to reduce dependence on SIAs and measles susceptibility in our context, this analysis underscores the significant value derived from integrating these diverse datasets. Therefore, beyond the integration of serosurveys into disease surveillance, it is imperative to enhance routine vaccination coverage and case surveillance data for optimal disease control. I have also demonstrated the enhanced utility of integrating seroprevalence data into modelling frameworks for outbreak risk prediction, particularly in situations relying on herd protection thresholds, such as in measles control programs. This approach is valuable for rapidly assessing the potential impacts of healthcare system disruptions and gauging progress toward measles elimination. I have demonstrated the value of serosurveillance data in monitoring the effective coverage of immunisation programs. This approach offers additional advantages compared to crude vaccination coverage as it provides insights into the population protected against infection or disease. I consider this method as a valuable means to identify vaccination gaps, especially in communities with inadequate record-keeping, which can be addressed during immunisation campaigns. However, it is essential to carefully consider the cost implications and logistical challenges associated with serologic testing in relation to the potential benefits of incorporating immune markers for vaccination monitoring. Finally, I have illustrated how these estimates can be utilised to assess the effectiveness of a vaccination program, either independently as demonstrated with rubella or through integration into a modelling framework as exemplified with Hepatitis B. This proves invaluable, especially when evidence is required for potential revisions to existing vaccination programs. Collectively, the research in this thesis addresses the value of information added by serological surveys in control of VPDs in an LMIC setting.
Item Type | Thesis |
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Thesis Type | Doctoral |
Thesis Name | PhD |
Contributors | Adetifa, I M; Flasche, S and Ojal, J |
Faculty and Department |
Faculty of Epidemiology and Population Health Faculty of Epidemiology and Population Health > Dept of Infectious Disease Epidemiology & Dynamics (2023-) |
Funder Name | African Research Leader Fellowship, Bill and Melinda Gates Foundation, Wellcome Trust, Foreign, Commonwealth and Development Office |
Grant number | MR/S005293/1, INV-039626, DEL-15-003 |
Copyright Holders | Caroline Mburu |
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Filename: 2024_EPH_PhD_Mburu_C.pdf
Licence: Creative Commons: Attribution-Noncommercial-No Derivative Works 4.0
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