Analytic insights into the population level impact of imperfect prophylactic HIV vaccines

Laith J. Abu-Raddad, Marie Claude Boily, Steve Self, Ira M. Longini

Research output: Contribution to journalArticle

11 Citations (Scopus)


The population level implications of imperfect HIV vaccines were studied using a mathematical model. A criterion for determining the utility of a vaccine at the population level is introduced, and 2 useful summary measures, namely, vaccine utility (φ) and vaccine infection fitness (ψ), are derived and shown to characterize the population-level utility once vaccine efficacies are determined. The utility of the vaccine alone does not guarantee a substantial impact, however, because the effectiveness of partially effective vaccines also depends on the prevailing level of HIV infectious spread. Therefore, a second criterion is introduced through a third summary measure, the hazard index (ξ), to describe the effectiveness of a vaccine in substantially reducing HIV incidence. The qualitative features of the impact are delineated by studying 4 distinct scenarios of HIV vaccination. Accordingly, our work delineates the link between vaccine efficacies and the impact of vaccination at the population level and provides the tools for vaccine developers to assess the utility and effectiveness of a given imperfect vaccine straightforwardly and rapidly.

Original languageEnglish
Pages (from-to)454-467
Number of pages14
JournalJournal of Acquired Immune Deficiency Syndromes
Issue number4
Publication statusPublished - 1 Aug 2007



  • HIV
  • Infectious disease
  • Mathematical model
  • Vaccine efficacy
  • Vaccines

ASJC Scopus subject areas

  • Infectious Diseases
  • Pharmacology (medical)

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