Just when it seemed no new variant would appear.
Not sure why you'd think there'd be no new variants.
There will always be new variants to any disease. It's what they do, i.e. mutate over time. Hence why there's always a different flu jab every year, i.e. to try to protect against whatever strain of flu will be the most dangerous/virulent that Winter.
Likewise, why it's expected that covid jabs will be required at least every Autumn, maybe more often, to protect against the latest variants.