that the u.s. has earmarked for poorer countries. this is a big commitment the administration is making to get vaccine out to much of the world. but this rollout's going to take you into next year. is it enough? is the timing going to work out? >> well, it's an extraordinary commitment. it's without any precedent. far and away, the largest purchase. a half-billion doses purchased by the u.s., to be donated to the hundred lowest-income countries in the world. those doses will start to be manufactured in august. and we will have plans to get them immediately out to countries with plans to, then, get shots in challenge for the president to meet that 70% goal. 70% of americans, adults, with at least one shot in their arms. why is it so challenging? >> well, we are at 64%. and we got a few weeks to go to july 4th. we are doing everything we can to make it as easy as possible for americans to get vaccinated.