The UK government is in "advanced discussions" with Moderna to ensure access to its vaccine by spring next year - with results showing the jab is 94.5% effective.
The vaccine, which Moderna produced in collaboration with the US government's "Operation Warp Speed", 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.
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 the much lower temperature of -70C.
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So far, the UK government has secured early access to six candidate vaccines - totalling more than 350 million doses - which includes the Pfizer vaccine but not the Moderna vaccine.
However, the UK government said it was in advanced discussions with Moderna to also ensure access to their vaccine, but said this might not be until spring next year "at the earliest".
A spokesperson said: "The news from Moderna appears to be good and represents another significant step towards finding an effective COVID-19 vaccine.
"As part of the ongoing work of the vaccines taskforce, the government is in advanced discussions with Moderna to ensure UK access to their vaccine as part of the wider UK portfolio.
"Moderna are currently scaling up their European supply chain which means these doses would become available in spring 2021 in the UK at the earliest.
"To date, the UK government has secured early access to 350 million vaccines doses through agreements with six separate vaccine developers.
"This includes 40m doses of Pfizer/BioNTech's vaccine, which is based on the same platform as Moderna's vaccine and if approved by the medicines regulator, is expected to begin delivery as early as December 2020."
Moderna's president, Dr Stephen Hoge, said he "grinned ear to ear" when learning about the potential efficacy of the vaccine.
He told BBC News: "When we got the news from the data and safety monitoring board, I'll admit I broke character and grinned ear to ear for a minute.
"Because I didn't expect, I don't think any of us really hoped, that the vaccine would be 94% effective at preventing COVID-19 disease, that was really a stunning realisation."
He said combined with data suggesting it can stop severe coronavirus, it means "that the vaccine really is a terrific tool for stopping the pandemic and hopefully stopping the worst of the disease that people are facing".
He added: "When you combine it with the news of last week of Pfizer's vaccine, you've got now two vaccines that are over 90% effective.
"It really means I think we have the tools necessary to finally beat this virus back and I think that's probably the best news of the day for all of us, is that there really are now solutions in our hands and we need to deliver them to the people who can use them."
The US government have an agreement for 100 million doses of the Moderna vaccine, while the EU concluded "exploratory talks" with the company earlier this year that could result in it purchasing up to 160 million doses.
US President Donald Trump tweeted: "Another Vaccine just announced. This time by Moderna, 95% effective.
"For those great "historians", please remember that these great discoveries, which will end the China Plague, all took place on my watch!"
President-elect Joe Biden also tweeted: "Today's news of a second vaccine is further reason to feel hopeful. What was true with the first vaccine remains true with the second: we are still months away.
"Until then, Americans need to continue to practice social-distancing and mask-wearing to get the virus under control."
Both the Pfizer and Moderna vaccines use 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.
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."
Peter Openshaw, professor of experimental medicine at Imperial College London, said: "This news from Moderna is tremendously exciting and considerably boosts optimism that we will have a choice of good vaccines in the next few months.
"First we heard 90% efficacy from Pfizer and BioNTech, then the Russians said 92% and now Moderna says 94.5%.
"This latest press release is based on a study of 30,000 US adults, including many high-risk or elderly persons.
"This gives us confidence that the results are relevant in the people who are most at risk of COVID-19 and in most need of the vaccines."
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."
Global stock markets - already buoyed by last week's Pfizer vaccine announcement - raced higher again on the update from Moderna.
The FTSE 100 rose by nearly 2%, or more than 100 points, while there were similar gains for France's Cac 40 and Italy's MIB.
Markets have been recovering in recent weeks from an October dip caused by fears over the impact of a second wave of coronavirus infections and further lockdowns.
Earlier on Monday, Prime Minister Boris Johnson expressed his hope that "those who really need it" might receive a COVID-19 vaccine "perhaps before Christmas".
Speaking to Sky News' Kay Burley, Health Secretary Matt Hancock described the roll-out of a vaccine as a "huge administrative challenge".
"Even if that comes through as fast as it possibly could, the majority of people we'd expect to be vaccinating in the New Year even if we do manage to make progress this year," he said.
"We are not there yet, we don't yet have a vaccine signed off."
Vaccine candidates proving far more effective than scientists could have hoped for
Analysis by Thomas Moore, science correspondent
There are seven billion people across the planet who would need vaccination. That means manufacturers are likely to need huge numbers of factories to churn out the required doses.
In the UK, the government has secured six different vaccines, 350 million doses in all - the idea being to spread your bets in the hope of securing at least one successful vaccine.
There was no guarantee that any of the vaccines were actually going to produce a good response. That's the reason the government went with AstraZeneca and Pfizer.
There was a good result with Pfizer last week and we are expecting AstraZeneca to come back any day now with their results.
All the vaccines that have reported so far are in the same ballpark around 90% to 94% effectiveness, so things are already much better than scientists had hoped for.
The Moderna vaccine is much easier to distribute than the Pfizer jab, which has huge problems.
Not only does the Pfizer jab have to be kept very cold, but it has to be mixed with another liquid before it can be given.
It's not a simple pull out of the package and inject it into the arm that GPs would be used to, so there are considerable advantages for going with another vaccine.
The problem is Moderna is not a part of the UK stockpile. My understanding is there were concerns about the European supply chain.
That is now being addressed and that is why the government is looking again at its ability to put this vaccine into the UK stockpile.