Pfizer and BioNTech

U.S.-based pharmaceutical giant Pfizer and German biotech company BioNTech were already collaborating to come up with a flu vaccine based on a genetic material called mRNA. When COVID-19 emerged, they quickly agreed to partner to test candidates developed by BioNTech that, just under a year later, led to the first COVID-19 vaccine authorized for emergency use by the U.S. FDA. Pfizer’s experience in conducting clinical trials demonstrated, in record time, that the companies’ vaccine was 95% efficacious in protecting people from COVID-19—which was confirmed in real-world studies involving millions of vaccinated people—and its scale will help produce an expected 2.5 billion doses in 2021.

Correction, April 29

This story’s original photo caption misstated Türeci and Sahin’s location. They were in Mainz, Germany; not at a production facility in Marburg, Germany.

Contact us at letters@time.com.