The Novavax vaccine is 96% effective in preventing cases caused by the original version of the coronavirus, a UK study has found.
New data released on Thursday confirmed the jab - which the UK has ordered 60million doses of - was found to be 100% effective in preventing serious illness and death.
Novavax Inc released results from two clinical trials on various strains of the virus, one held in the UK and another in South Africa.
Scientists tested the vaccine on the highly contagious strain of Covid-19 first discovered in Kent and found it to be 86% effective in protecting against the variant.
The means it has combined 90 per cent effectiveness rate overall based on data from infections of both versions of the coronavirus.
Novavax Inc said there were no cases of severe illness or deaths among those who got the vaccine, in a sign that it could stop the worse effects of new variants.
However, in South Africa, the Novavax jab was found to only be 55.3% effective against the native variant.
The UK has ordered 60million doses of the Novavax jab.
Stanley Erck, president and CEO of Novavax, said: "We are very encouraged by the data showing that NVX-CoV2373 not only provided complete protection against the most severe forms of disease, but also dramatically reduced mild and moderate disease across both trials.
"Importantly, both studies confirmed efficacy against the variant strains.
"Today marks one year since the WHO officially declared the Covid-19 pandemic, and with this data in hand, we are even more motivated to advance our vaccine as a potential weapon in the fight to end the suffering caused by Covid-19."
It comes as the first results of the UK vaccination programme suggests it is having an impact on preventing serious illness.
Research led by Public Health Scotland found at four weeks after the first dose, hospital admissions were reduced by 85% and 94% for the Pfizer and AstraZeneca jabs.
