The success of the UK’s vaccine roll-out is cause for cautious optimism. But securing the population its double doses won’t be the end of the road for Covid vaccination. Uncertainties about supply, re-vaccination and adapting existing vaccines lie ahead.

“It’s very unlikely that re-vaccination will be any more frequent than once a year – and perhaps even every two years,” says Professor Robert Dingwall, a medical sociologist from Nottingham Trent University and a researcher in genetics and evolution. For vulnerable groups, it may well mirror the flu vaccine: “Both will be annual visits to the GP – flu jab in the autumn, Covid vaccine in the spring”.