Population Perspectives and World Health Organization Recommendations for CYD-TDV Dengue Vaccine

(See the correspondence by Halstead on page 2014.) In late 2015, after decades of research, the world's first dengue vaccine was licensed. Data generated by a comprehensive and very large phase 3 clinical trial program for the CYD-TDV vaccine (Dengvaxia), developed by Sanofi Pasteur [1], in 10 dengue-endemic countries in Asia and Latin America [2, 3] revealed complex findings for the vaccine's performance, which were unpredicted and unprecedented. Nevertheless, and apart from significant imperfections of the vaccine, it qualifies as an additional tool in the scarce armamentarium for dengue control. In light of the rising incidence of a disease currently estimated to clinically affect about 100 million individuals annually [4], this is a major step forward. In his article in The Journal of Infectious Diseases [5], Halstead stated in the title that “WHO approves the CYD-TDV dengue vaccine”. This statement is misleading, and it is hence important to elaborate on the role of the World Health Organization (WHO). It does not fall under the purview of the WHO to approve vaccines; the power to license vaccines belongs to national regulatory authorities who follow their own rigorous evaluations and approval processes on the basis of the quality, safety, and efficacy of the product. The WHO provides guidance to member states on health policy matters, to assist in their decision making. In the case of immunization, WHO guidance is based on the input of the Strategic Advisory Group of Experts (SAGE) [6], the principal independent advisory group to the WHO on global policies and strategies for vaccines and immunization. SAGE follows an exacting process of evidence review and makes recommendations transparently and in an open forum. SAGE working groups are supplemented with additional independent, disease-specific expertise, and these working groups review the evidence and propose recommendations for further SAGE consideration.