MAINZ, GERMANY - APRIL 22: The headquarters of German immunotherapy company BioNTech stands on April 22, 2020 in Mainz, Germany. BioNTech and U.S. pharmaceutical giant Pfizer announced today that German authorities have granted them approval to begin clinical trials for BioNTech's BNT162, a possible vaccine against Covid-19. BioNTech will conduct the trial in Germany with 200 participants while Pfizer will conduct its trial in the United States once regulatory authorities grant the trial there. (Photo by Thomas Lohnes/Getty Images)