Epidemiological and economic modelling of pharmaceutical interventions for respiratory disease in low- and middle-income settings

Abstract

The COVID-19 pandemic brought unprecedented visibility to the use of modelling to inform health policy. Restricted healthcare budgets and workforce capacity motivate an understanding of the relative benefits of these policies. This Thesis uses epidemiological and economic models to explore the best use of pharmaceutical interventions in low- and middle-income settings. I present five case studies modelling oral antivirals and vaccines for COVID-19, pneumococcal disease, and emerging infectious diseases in Fiji, Indonesia, Papua New Guinea, Sierra Leone, and Timor-Leste.

My first theme of research concerns the use of compartmental models to quantify the setting-specific impact of interventions for infectious disease. I demonstrate how differences in age structure, prevalence of comorbidities, vaccine hesitancy, and vaccine- and infection-derived immunity explain differences in the impact of interventions by setting. I find that prioritising individuals at the highest risk of developing severe outcomes is the best way to minimise severe disease when circulation is high. I demonstrate how age- and risk-based prioritisation improve the impact of interventions.

In my second theme of research, I conduct cost-effectiveness analysis of COVID-19 oral antivirals and booster doses, and a maternal pneumococcal vaccine. I identify the price of interventions as the main driver of their cost-effectiveness, particularly during the introduction of new interventions. My modelling supports negotiations on more appropriate pharmaceutical prices for low- and middle-income countries. I emphasise the importance of including decision-makers in the design of economic evaluations by showing how the choice to discount future health outcomes and selection of a cost-effectiveness threshold determines whether interventions are deemed cost-effective.

My final theme of research draws together insights on maximising the use of vaccines in future pandemics. I demonstrate the potential of the Coalition for Pandemic Preparedness' mission to develop and deliver vaccines within one hundred days of the next pandemic. I argue that the effective use of vaccines in future pandemics will depend on understanding age-specific severity, estimating the strength of infection- and vaccine-derived immunity, and prior experience delivering vaccines to high-risk groups. I call for better data identifying vulnerable groups in low- and middle-income countries. Show more