Dengue is endemic in the U.S. territories of American Samoa, Guam, Puerto Rico and the U.S. Virgin Islands.The safety and effectiveness of the vaccine was determined in three randomized, placebo-controlled studies involving approximately 35,000 individuals in dengue-endemic areas, including Puerto Rico, Latin America and the Asia Pacific region. The vaccine was determined to be approximately 76 percent effective in preventing symptomatic, laboratory-confirmed dengue disease in individuals 9 through 16 years of age who previously had laboratory-confirmed dengue disease. Dengvaxia has already been approved in 19 countries and the European Union.Dengvaxia is not approved in the U.S. for use in individuals not previously infected by any dengue virus serotype or for whom this information is unknown.Dengvaxia is a live, attenuated vaccine that is administered as three separate injections, with the initial dose followed by two additional shots given six and twelve months later.The U.S. Food and Drug Administration (FDA) granted the application for Dengvaxia priority review designation and a tropical disease priority review voucher. The approval of Dengvaxia was granted to Sanofi Pasteur. CYD-TDV (Dengvaxia)
CYD-TDV, sold under the brand name Dengvaxia and made by Sanofi Pasteur, is a live attenuated tetravalent chimeric vaccine made using recombinant DNA technology by replacing the PrM (pre-membrane) and E (envelope) structural genes of the yellow fever attenuated 17D strain vaccine with those from the four dengue serotypes.
In November 2017, Sanofi acknowledged that some participants were put at risk of severe dengue if they had no prior exposure to the infection; subsequently the Philippine government suspended the mass immunization program with the backing of the WHO which began a review of the safety data.Phase III trials in Latin America and Asia involved over 31,000 children between the ages of two and 14 years. In the first reports from the trials, vaccine  efficacy was 56.5% in the Asian study  and 64.7% in the Latin American study in patients who received at least one injection of the vaccine. Efficacy varied by serotype. In both trials vaccine reduced by about 80% the number of severe dengue cases. An analysis of both the Latin American and Asian studies at the 3rd year of follow-up showed that the efficacy of the vaccine was 65.6% in preventing hospitalization in children older than nine years of age, but considerably greater (81.9%) for children who were seropositive (indicating previous dengue infection) at baseline. The vaccination series consists of three injections at 0, 6 and 12 months. The vaccine was approved in Mexico, Philippines, and Brazil in December 2015, and in El Salvador, Costa Rica, Paraguay, Guatemala, Peru, Indonesia, Thailand and Singapore in 2016. Tradenamed Dengvaxia, it is approved for use for those aged nine and older and can prevent all four serotypes.