title: The Impact of the Newly Licensed Dengue Vaccine in Endemic Countries.
abstract: With approximately 3 billion people at risk of acquiring the infection, dengue fever is now considered the most important mosquito-borne viral disease in the world, with 390 million dengue infections occurring every year, of which 96 million manifest symptoms with any level of disease severity. Treatment of uncomplicated dengue cases is only supportive and severe dengue cases require hospital intensive care. A vaccine now licensed in several countries and developed by Sanofi Pasteur (CYD-TDV, named Dengvaxia), was able to protect, in the first 25 months of the two Phase III, 66% of a subset of 9-16 year old participants. However, a significantly lower efficacy (including negative vaccine efficacy) was noted for children younger than 9 years of age.
  
  
  
  Analysis of year 3 results of phase III trials of Dengvaxia suggest high rates of protection of vaccinated partial dengue immunes but high rates of hospitalizations during breakthrough dengue infections of persons who were vaccinated when seronegative, with vaccine appearing to induce enhancing antibodies (ADE). An age structured model was developed based on Sanofi's recommendation to vaccinate persons age 945 years in dengue endemic countries. The model was used to explore the clinical burden of two vaccination strategies: 1) Vaccinate 4 or 20% of individuals, ages 9-45 years, seropositives and seronegatives, and 2) vaccinate 4 or 20% of individuals, ages 9-45 years, who are dengue immune only.
  
  
  
  Our results show that vaccinating dengue monotypic immune individuals prevents dengue hospitalizations, but at the same time dengue infections of vaccine-sensitized persons increases hospitalizations. When the vaccine is given only to partial immune individuals, after immunological screening of the population, disease burden decreases considerably.
authors.affiliation: Center for Mathematics, Fundamental Applications and Operations Research, Lisbon University, Lisbon, Portugal.
authors.forename: Maíra
authors.identifier: 0000-0001-8354-9944
authors.initials: M
authors.lastname: Aguiar
authors.affiliation: Center for Mathematics, Fundamental Applications and Operations Research, Lisbon University, Lisbon, Portugal.
authors.forename: Nico
authors.initials: N
authors.lastname: Stollenwerk
authors.affiliation: Department of Preventive Medicine and Biometrics, Uniformed Services University of the Health Sciences, Bethesda, Maryland, United States of America.
authors.forename: Scott B
authors.initials: SB
authors.lastname: Halstead
mesh_terms: D000293:Adolescent; D000328:Adult; D057134:Antibodies, Neutralizing / Q000276:immunology; D000914:Antibodies, Viral / Q000276:immunology; D002648:Child; D017326:Clinical Trials, Phase III as Topic; D003715:Dengue / Q000453:epidemiology / Q000276:immunology* / Q000517:prevention & control* / Q000821:virology; D053059:Dengue Vaccines / Q000008:administration & dosage / Q000009:adverse effects* / Q000276:immunology* / Q000592:standards; D003716:Dengue Virus / Q000276:immunology; D019353:Endemic Diseases / Q000517:prevention & control / Q000706:statistics & numerical data; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D008297:Male; D008875:Middle Aged; D019595:Severe Dengue / Q000276:immunology / Q000517:prevention & control / Q000821:virology; D014611:Vaccination / Q000331:legislation & jurisprudence / Q000592:standards / Q000706:statistics & numerical data*; D014613:Vaccines, Attenuated / Q000276:immunology; D055815:Young Adult
chemical_list: D057134:Antibodies, Neutralizing; D000914:Antibodies, Viral; D053059:Dengue Vaccines; D014613:Vaccines, Attenuated