Abstract

ObjectivesMathematical models have unanimously predicted that a first-generation HIV vaccine would be useful and cost-effective to roll out, but that its overall impact would be insufficient to reverse the epidemic. Here, we explore what factors contribute most to limiting the impact of such a vaccine.\n\nMethodsRanging from a theoretical ideal to a more realistic regimen, mirroring the one used in the currently ongoing trial in South Africa (HVTN 702), we model a nested hierarchy of vaccine attributes such as speed of roll-out, efficacy, and retention of booster doses.\n\nResultsThe predominant reasons leading to a substantial loss of vaccine impact on the HIV epidemic are the time required to scale up mass vaccination, limited durability and waning of efficacy.\n\nConclusionsA partially effective HIV vaccine will be a critical milestone for the development of a highly effective, durable, and scalable next-generation vaccine. Accelerated development, expedited vaccine availability, and improved immunogenicity are the main attributes of a vaccine that could dramatically reverse the course of the epidemic in highly endemic countries.