That UK report suggests that protection from symptomatic infection reduces (at the 10 week mark) for Pfizer, but not for Moderna.

It reduces for both, but Moderna's still high at that "9+" week mark because of the larger dose. It's only reasonable to assume that it will plummet fast as more weeks pass. Notice also how the AstraZeneca vaccinated are disadvantaged yet again: they both have less protection in the first place and lose protection no matter what booster they get.

The conclusion is that the current boosters are essentially obsolete for infection control. When considering also the risk of myocarditis, vaccine mandates in colleges don't make sense.

>for males younger than 40, risk of myocarditis from the vaccine and disease is similar.

When a person has COVID-19, is myocarditis the only symptom that can kill them?

Total risk of death and injury from COVID-19 is far greater than the total risk of death and injury from vaccine-induced symptoms.

Mandating boosters is very easily justified.

It’s may not be justified, because the subjects are already vaccinated and protected, but there is an increase in myocarditis risk for them.

Protection from the vaccine wanes over time. For the entire population, boosters reduce COVID-19 death/injury more than they increase vaccine death/injury.

Many European countries are segmenting the population by age and making different recommendations for different segments.

Creating policies "for the entire population" is irresponsible given that we know that these vaccines have side-effects which are more frequent at specific age spans, so I expect that the appropriate institutions are verifying the latest data and are adjusting their recommendations. This is generally happening e.g. in the UK or Germany.