The Covid-19 vaccine developed by Pfizer and BioNTech generates robust immunity after one dose and can be stored in ordinary freezers instead of at ultracold temperatures, according to new research and data released by the companies.

The findings provide strong arguments in favour of delaying the second dose of the two-shot vaccine, as the UK has done. They could also have substantial implications on vaccine policy and distribution around the world, simplifying the logistics of distributing the vaccine.