Sanofi S.A. is a French multinational pharmaceutical company based in Paris, France, as of 2013 the fifth largest prescription sales in the world. Originally, the company was founded in 1973 and merged with Synthélabo in 1999 to form Sanofi Sentelabo. In 2004, Sanofi-Cynthiabo merged with Aventis and was renamed Sanofi-Aventis, each the product of several previous mergers. She changed her name back to Sanofi in May 2011. The company is an element of the European Stock Market Index Stoxx 50. Sanofi is involved in research, development, manufacturing and marketing of pharmaceutical drugs mainly in the prescription market, but the company also develops over-the-counter drugs. The company covers seven main therapeutic areas: cardiovascular, central nervous system, diabetes, internal medicine, oncology, coagulation and vaccines (the world's largest producer of the latter through its Sanofi Pasteur subsidiary). In 2017, Sanofi Dingafaxia's dengue vaccine sparked controversy because it caused some young children vaccinated to have more severe dengue fever. The New York Times reported criticism of Sanofi's aggressive advertising campaign despite the fact that the new vaccine was not entirely safe.