The best analogy I’ve heard to describe the trend comes from Ashish Jha, dean of Brown University’s School of Public Health: Consider what happens when a new iPhone is launched. When a new model is released, some people are so excited that they will wait in line overnight to get it. While superfans aren’t the only ones who buy iPhones, they do drive up initial demand. Many America’s who have had the Vaccine so far have done the same thing: they got Vaccine as soon as they were qualified.
The remaining unvaccinated individuals aren’t all completely apprehensive or resistant to Vaccine. Consider Vaccine excitement as a continuum, with some America’s eager to get the shot, others unable, and many others in between. The US will finally need to make inroads with the hard noes, but for now, the people in the middle are the low-hanging fruit. They would gladly take the if it were right in front of them, but they can’t take time off work or don’t want to devote hours of their day to getting a shot.