If I understood Dr. Murphy on WGN this morning, it's kinda a weird result. If they gave people the full dose first and then the booster dose, it was only 60%. But there was a subset of 3000 participants that got a half dose first and then the full dose, and this group had 90% effective. When you combine the two, that's where you get the 70%. He had never heard of a vaccine like that before, but AZ/Oxford obviously had some preliminary research that made them think to try this.