The <45years of age US population in 2010 accounted for 60% of the total. Depending on what the threshold for herd immunity actually is, it could be "enough" to

The <45years of age US population in 2010 accounted for 60% of the total. Depending on what the threshold for herd immunity actually is, it could be "enough" to have everybody outside risk groups vaccinated. Even if we don't achieve herd immunity then, it does put us closer to it, meaning fewer people in the risk population would die. https://www.census.gov/prod/cen2010/briefs/c2010br-03.pdf https://www.census.gov/prod/cen2010/briefs/c2010br-03.pdf