I assume in both countries the people that were first vaccinated are similar, eg first the health workers and the aged. Now that would beeven more diverse ages in the uk, due to them having vaccinated a lot more percentage of people, about 50% ppl have had a shot, median age in uk is what? 36 or so I guess
edit:seems median age is 40.5 in UK
https://www.bbc.com/news/health-55274833
so more than 30 million ppl have had a shot already, remaining pop under 50 = 21 million which means they already must of vaccinated close to 10 million under the age of 50