London — A US-developed vaccine has been shown to be 94.5% effective at protecting people from COVID-19, according to interim results.

Produced by Moderna, in collaboration with the US government’s “Operation Warp Speed”, the vaccine has also been shown to last for up to 30 days in household fridges and at room temperature for up to 12 hours, Skynews reported.

It also remains stable at -20C, equal to most household or medical freezers, for up to six months.

This suggests it can be stored and transported much more easily than a Pfizer/BioNTech vaccine, which was last week announced to be 90% effective at protecting people from coronavirus.

The Moderna vaccine is not expected to be available outside the US until next year. The biotech said it would have 20 million doses ready to ship in the US before the end of 2020 and hoped to manufacture 500 million to one billion doses globally next year.