The mortality data for England and Wales from ONS from 1 May 2021 until 17 September 2021 shows a significant excess, particularly in the 15-19 year age group. Depending on the baseline chosen, the excess for 15-19 year olds is between 16% and 47% above expected levels (see table 1 and 2). COVID-19 deaths were too small in number to account for the excess. A disproportionate number of these excess deaths were in males. A certain amount of variation by random chance would be expected but an increase of this proportion is large enough not to be dismissed without further investigation.
…Mortality has risen in younger age groups since 1st May 2021. The increase in the 15-19 year old age group is particularly noticeable, especially as deaths in this age group are uncommon. The excess deaths have a marked male predominance. An increase in ambulance call outs for patients who have had a cardiac arrest or are unconscious showed a coincidental noticeable rise from May 2021. The period also coincides with the rollout of vaccination. Finally, ONS have reported on a striking rise in age adjusted mortality rates in those with only one dose that accelerated in May 2021 to levels far exceeding those in the unvaccinated.
https://www.hartgroup.org/recent-deaths-in-young-people-in-england-and-wales/