“I am seeing the storm clouds gathering over parts of the European continent,” Boris Johnson said last week. “We have been here before and we remember what happens when a wave starts rolling in.”

The prime minister’s warning was full of foreboding for anybody who lived through last year’s winter – when a doggedly optimistic government refused to countenance imposing coronavirus restrictions over Christmas, only to be forced to reverse its position at the last minute. The move confirmed the seriousness of a long, grim second wave that proved even deadlier than the first – and fundamentally changed the way many of us thought about coronavirus, dispelling all hopes that we would soon be able to turn the page and go back to life as it was before.

A year on, Johnson is right: the situation in Europe is troubling. In Germany, cases are at their highest level since the start of the pandemic. In the Netherlands, curfews and orders that sporting fixtures be played in empty stadiums are back in place. In Croatia, the daily death rate is higher than it was a year ago. Last week, Reuters reported that the continent accounted for more than half of infections in the world, and about half of new deaths.

For the UK, that is ample reason for concern – but there are also reasons to be more optimistic. In this episode, the Guardian’s science editor, Ian Sample, talks to Nosheen Iqbal about that complicated picture. He explains why the situation might be different across the Channel, reflecting on factors from the early prevalence of the Delta variant in the UK to vaccination rates. And he looks ahead to the possible impact of antiviral treatments, which have the potential to make a significant dent in the damage caused by Covid-19. Finally, he answers the question on every listener’s lips: will he be going to Christmas parties?