On Apr. 14, 2020, Sanofi and GSK announced that they had signed a letter of intent to enter into a collaboration to develop an adjuvanted vaccine for COVID-19, using innovative technology from both companies, to help address the ongoing pandemic.

Sanofi will contribute its S-protein COVID-19 antigen, which is based on recombinant DNA technology. GSK will contribute its proven pandemic adjuvant technology to the collaboration.