This will become apparent pretty readily in late January 2015 -- when the "head to head" clinical trials in volunteer human subjects begin, in Africa. But it is worth noting that if GSK needs to make say twice as much vaccine conjugate, in order to get the same "yield" for a final vaccine as Merck, the sheer size of the undertaking may mean that Merck wins the race. We shall see -- here's a bit, from Medical News Today:
. . . .The [GSK candidate] vaccine comprises a harmless "carrier virus" - which causes a common cold in chimpanzees and does not cause illness in humans - and genetic material from two strains of Ebola virus: the Sudan strain and the Zaire strain.
The vaccine does not contain Ebola virus and cannot cause Ebola disease, say the developers.
In total, 20 healthy people aged 18-50 volunteered for the trial. Of these, 10 people received a low dose, and 10 received a high dose of the vaccine via intramuscular injection. . . .
The highest levels of antibodies were found in the volunteers who received the higher dose of vaccine. . . .
As I say -- we will learn much more, and pretty quickly, come January 2015. Enjoy your turkey -- and stuffing!