Successful Phase-3 trials commencing in May 2021 in Asia, Africa and Latin America involving 10,000 adults were conducted by biopharmaceutical companies Sanofi of France and GSK of the U.K. Encouraging results were obtained using a protein subunit vaccine against COVID.  The Sanofi-GSK vaccine to be released as Vidprevtyn® was tested against both the pathogenic Delta and infectious Omicron variants in circulation. The vaccine was 100 percent effective against severe COVID with respect to preventing hospitalization.  It was less effective than mRNA vaccines in preventing mild COVID symptoms.  An advantage of the conventional vaccine is that it can be stored under conventional refrigeration temperature and will be suitable for developing nations where deployment of mRNA vaccines is complicated by storage and distribution.

The vaccine was developed using a $2.1 billion grant from the U.S. Operation Warp Speed initiated by the previous Administration.  It is anticipated that the vaccine will provide immunity with two doses administered at three-week intervals.  Approximately 100 million doses of Vidprevtyn® have been manufactured and Sanofi indicated that an additional 400 million doses will soon be available.