Most recently, Sanofi Pasteur’s recombinant, live, attenuated Chimeric Yellow Fever-Tetravalent Dengue Vaccine (CYD-TDV), that expresses preM and env proteins of Dengue virus, became the first Dengue vaccine to be approved for human use for the prevention of Dengue virus infection by two countries; Mexico36 and Philippines37. The gene discussed is ERVW-1; the disease is dengue disease.