(Sky News)

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.

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.

Following last week’s news, governments around the world – including the UK – had been scrambling to deal with the logistical challenge of deploying the Pfizer vaccine, which is required to be stored at much lower temperatures.

So far, the UK government has secured access to six candidate vaccines, which includes the Pfizer vaccine but not the Moderna vaccine.

However, a Whitehall source said the UK government was in “advanced negotiations” with Moderna.

Both the Pfizer and Moderna vaccines use a technology known as mRNA, which introduces into the body a messenger sequence that contains the genetic instructions for the vaccinated person’s own cells to produce the antigens and generate an immune response.

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Stephane Bancel, Moderna’s chief executive, hailed “a pivotal moment” in the company’s development of a COVID-19 vaccine.

He said: “Since early January, we have chased this virus with the intent to protect as many people around the world as possible. All along, we have known that each day matters.

“This positive interim analysis from our Phase 3 study has given us the first clinical validation that our vaccine can prevent COVID-19 disease, including severe disease.”

Responding to the interim analysis of the Moderna vaccine, Professor Trudie Lang, director of the Global Health Network at the University of Oxford, said: “It is very good news indeed to see another vaccine coming through with similar efficacy results as were reported last week from Pfizer.

“This is also an interim analysis, which means that there were enough cases within the vaccinated volunteers to give statistical significance and allow the team to break the blind to determine who had the active vaccine and who had placebo.

“Here they found that of 95 cases of COVID, 90 had received the placebo and five the active vaccine.

“These early results suggest that there was a representation across different age groups and diverse communities in the protected group.

“This is really encouraging and it further demonstrates that a vaccine for COVID is a real probability and that having more than one supplier should help assure better and more equitable global availability.

“This vaccine is also an mRNA vaccine, so many of the same questions remain as we have been discussing with the Pfizer vaccine and these will be looked at carefully by the regulators.”

Related: Pfizer says COVID-19 vaccine is looking 90% effective