It feels eerily familiar: end-of-lockdown excitement, meeting friends in the sunshine, and even the possibility of a holiday abroad. The numbers are almost identical too. Last year, as this May, new Covid-19 cases drifted well below 2,000 a day. Then as now, summer (and freedom) was unleashed at last. But we know how 2020 ended. A brutal spike and an equally brutal lockdown. Educations were trashed. Christmas was cancelled. So if we do – as many suspect we will – get a new winter take-off of what appears an ever-more seasonal virus, will we face the same misery again? Vaccine threats Last year, cases began to pick up again towards the end of August, and by the end of September were over 10,000 a day again. This time around, the Government hopes, vaccines will halt that rise. All adults will have had their first jab by the end of July. But there’s a wrinkle to the success of the rapid rollout, as the virus potentially surges back in the autumn the most vulnerable people, including the elderly, will have had the longest gap since their first injections. “We might see some immunity waning, particularly among older people,” said Prof Sarah Lewis, professor of molecular epidemiology, University of Bristol. No wonder that this week Vaccines Minister Nadhim Zahawi announced autumn boosters, most likely for everyone over 50. The second big threat is not waning antibodies, but new variants of the virus itself, which have previously shown they can be deadlier or spread faster, and partly elude the protection conferred by some current vaccines. The impact of such mutations can be dramatically seen in the statistics for last November, when the post-summer surge in cases was abating, only for a huge third wave to crash over Britain as we retreated indoors for winter. The “Kent variant” forced us into a new lockdown. As with waning antibodies, there is an official response to the variant threat too: the Government this week announcing almost £30 million to build labs at Porton Down specifically to monitor vaccines efficiency against worrisome mutations of the virus.