title: Vaccine preventable disease incidence as a complement to vaccine efficacy for setting vaccine policy.
abstract: Traditionally, vaccines have been evaluated in clinical trials that establish vaccine efficacy (VE) against etiology-confirmed disease outcomes, a measure important for licensure. Yet, VE does not reflect a vaccine's public health impact because it does not account for relative disease incidence. An additional measure that more directly establishes a vaccine's public health value is the vaccine preventable disease incidence (VPDI), which is the incidence of disease preventable by vaccine in a given context. We describe how VE and VPDI can vary, sometimes in inverse directions, across disease outcomes and vaccinated populations. We provide examples of how VPDI can be used to reveal the relative public health impact of vaccines in developing countries, which can be masked by focus on VE alone. We recommend that VPDI be incorporated along with VE into the analytic plans of vaccine trials, as well as decisions by funders, ministries of health, and regulatory authorities.
authors.affiliation: Agence de Médecine Preventive, 164 Rue de Vaugirard, 75015 Paris, France. Electronic address: bgessner@aamp.org.
authors.forename: Bradford D
authors.initials: BD
authors.lastname: Gessner
authors.affiliation: International Vaccine Access Center, Department of International Health, Johns Hopkins School of Public Health, Baltimore, MD, USA; Division of Preparedness and Emerging Infections, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA. Electronic address: dfeikin@jhsph.edu.
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Feikin
mesh_terms: D003140:Communicable Disease Control; D003141:Communicable Diseases / Q000453:epidemiology*; D006801:Humans; D015994:Incidence; D011634:Public Health; D014612:Vaccines
chemical_list: D014612:Vaccines
keywords: Cholera; Epidemiology; Haemophilus influenzae type b; Hib; Immunization; Malaria; Pneumococcus; RTS,S; Rotavirus; Streptococcus pneumoniae; Vaccine; Vaccine effectiveness; Vaccine efficacy
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