I would say, Mr. Chair, that the emergence of variants of concern has certainly added an important dimension to all of the work that we're doing under our vaccination strategy as we look at the effect on transmission and as we look at the effect on severity of disease.
It does not change the plans, of course, that we have for rollout of vaccines; that continues to happen, and that needs to happen as it has been set out, but as we look at the effectiveness of vaccines, for certain, variants of concern matter as we assess vaccine effectiveness.