Sanofi engages in the research and development, manufacturing and marketing of pharmaceutical drugs principally in the prescription market, but the firm also develops over-the-counter medication. The company covers seven major therapeutic areas: cardiovascular, central nervous system, diabetes, internal medicine, oncology, thrombosis and vaccines (it is the world's largest producer of the latter through its subsidiary Sanofi Pasteur). In 2017, Sanofi's dengue vaccine Dengvaxia garnered controversy because it caused some vaccinated young children to have more cases of severe dengue. The "New York Times" cited criticism for Sanofi's aggressive ad campaign despite the fact that this new vaccine was not completely safe.