It will depend on the supply dynamics. As you've identified, there are factors that come into this which are very difficult to predict, but there's a strong likelihood that people may be faced with receiving a second vaccine that is not the same as the first. That's why we've set up a study to look at every combination possible and understand what the risks and benefits of that might be. This study has been designed, but it will be a function of what comes through on supply and what that mix-and-match looks like.
However, we are in a position to study it and understand benefits and risks.