Why Sanofi's Coronavirus Vaccine Work Hasn't Helped Its Stock

French drugmaker Sanofi (NASDAQ: SNY) is at the forefront when it comes to the development of a coronavirus treatment or vaccine, and yet its shares haven't benefited from the efforts. While Sanofi has outperformed the S&P 500 index (down 26% this year), it has still lost 20% over that time. Meanwhile, the coronavirus outbreak became a pandemic, with cases now totaling more than 207,000 worldwide.