This is going to push us towards booster mandates (which also explains why the UK is looking to revise it's definition of fully vaxxed). IF it hold up, the other open question is how long does this immunity last. Just from anecdotal evidence of having spoken to various people with different experience of the booster, my gut tells me after the one booster, willingness to comply is going to drop severely, unless you get to the point that whatever the applicable product's side effects approach some point where they mirror the flu vaccine (and remember even with the flu vaccine we have only about 50% compliance depending on the jurisidiction)
www.ft.com

UK expands Covid booster jab programme to 40 to 49-year-olds
Children aged 16 and 17 will also be eligible for second dose to increase protection against infection