Economics of HIV Vaccines and HIV Vaccine Research and Development

Abstract

This thesis explores the economics of a prospective human immunodeficiency virus (HIV) vaccine in terms of: a) its cost-effectiveness in South Africa, and b) the opportunity cost of diverting vaccine R&D funds from other HIV prevention and control activities in South Africa. First, I use a mathematical and economic model of HIV vaccination in South Africa, exploring the cost-effectiveness of HIV vaccines with different attributes. I find that 1) vaccines with moderate initial efficacy but longer durations and smaller decay rates may have the same cost-effectiveness as a vaccine with high initial efficacy but short duration; 2) the vaccine’s cost-effectiveness decreases only slightly with higher vaccine coverage but dramatically with lower prevalence rate; and 3) more than one-third of the total benefit of a vaccine comes from its positive externality. Second, I compare the HIV vaccination as a potential preventive intervention versus PrEP. I find that 1) a vaccine with 60% initial efficacy, an 8-year duration, and a decay rate of γ = 3 is less effective than PrEP in reducing HIV prevalence and incidence from 2021 to 2035; 2) if PrEP has an efficacy of 90%, then we should charge a Thai Trial vaccine below $63, and an HVTN702 vaccine below $100 to make it preferable to PrEP. Finally, I examine the economic return on investing in R&D of an HIV vaccine, by comparing the return (in terms of infections averted) to the same level of investment into increasing uptake of existing HIV preventive interventions instead (ART, MMC and PrEP). I find that 1) the attributes of an HIV vaccine, and the probability of realizing them through R&D investment, determines the attractiveness of such investment relative to spending on alternative HIV interventions; and 2) a vaccine is much more preferable if the initial coverage of alternative interventions is higher.