Like a tedious series of horror movie sequels, the mutations of the Sars-Cov-2 virus are losing their power to shock. But the latest strains, which are adept at evading immunity, have spread fast.

Governments are trying to catch up. In late June, US government advisers recommended redesigning the Covid vaccine to target the Omicron variant. The UK government is also considering using the new generation of booster jabs when it offers a shot to all over-50s in the autumn — a wider campaign than originally planned.

The push should boost the flagging vaccine market. In April, vaccine tracker Airfinity cut its 2022 global sales forecast for Covid-19 jabs by 20 per cent to $64.1bn, saying demand had dropped. In the US, France, Germany and Italy fewer than one in 10 people are likely to take up a third booster on current trends. An updated vaccine, timed to coincide with flu jabs, would boost uptake.