The Novavax jab, which will be manufactured in Stockton-on-Tees, appears to be effective against both the original strain of coronavirus and a mutant strain first identified in Kent.

And it has shown around 60% effectiveness against the South African strain of coronavirus, which has been worrying scientists due to concerns vaccines may not work against it.

While the jabs from Pfizer/BioNTech and Moderna need to be kept at ultra-low temperatures, the Novavax jab is stable for up to three months in a normal fridge.

(Photo: JUSTIN TALLIS/AFP via Getty Images)

Here is everything you need to know about it.

How does it work?

Like other vaccines, the Novavax jab works by teaching the immune system to make antibodies to the coronavirus spike protein.

To create the vaccine, researchers inserted a modified gene into a virus, called a baculovirus, and allowed it to infect insect cells. Spike proteins from these cells were then assembled into nanoparticles which, while they look like coronavirus, cannot replicate or cause Covid-19.

A computer model showing the protein structure of a potential coronavirus vaccine at Novavax labs in Gaithersburg, Maryland (Photo: ANDREW CABALLERO-REYNOLDS/AFP via Getty Images)

These nanoparticles are then injected into the body via the vaccine where the immune system mounts an antibody response; if the body encounters coronavirus in the future, it is primed and ready to fend it off.

How effective is it?

The Novavax vaccine was shown to be 89.3% effective at preventing coronavirus in participants in its Phase 3 clinical trial.

The trial – part of which was conducted in the UK supported by the National Institute for Health Research – involved more than 15,000 people aged between 18-84, of which 27% were older than 65.

The study assessed how effective the vaccine was when transmission of Covid-19 was high in the UK, and with the variant strain first identified in Kent circulating widely.

The UK arm analysis, based on the first 62 cases of Covid-19 identified in the trial, reported 56 cases in people given a placebo (dummy) vaccine while six cases were in those given the Novavax jab.

This part of the trial showed the jab was 89% effective against Covid-19.

Does it work against mutant strains?

More than half of the UK arm’s cases related to the Kentish strain of the virus, with the vaccine offering 86% protection against this particular strain. Against the original strain that has circulated since the start of the pandemic, the vaccine was 96% effective.

In the South African arm of the trial, where most cases of Covid-19 were the South African strain, the jab was 60% effective in preventing mild, moderate and severe coronavirus.

Professor Peter Openshaw, from Imperial College London, said the finding for the South African variant was a “concern” due to suggestions that prior infection with earlier variants of Covid-19 may not completely protect against subsequent infection by the South African variant.

Novavax plans to immediately begin development on a vaccine specifically targeted to the South African variant, and scientists continue to be concerned about the strain of the virus that emerged in Brazil, with the expectation that it will not work as well with current vaccines.

Professor Paul Heath, the Novavax Phase 3 trial chief investigator, said he believed that vaccines could be adapted “at pace” to target new variants of coronavirus.

He told BBC Radio 4’s Today programme: “The technology we have both with this vaccine, the Novavax technology, and the other vaccines, it is such that they can adapt quickly so we can expect to see, if required, new vaccines.

"That now can be done at pace so that we can keep up with these variants should they prove to be difficult to prevent with the vaccine that we have at the moment," he added.

When will it be available?

The vaccine will now be assessed by the Medicines and Healthcare products Regulatory Agency (MHRA), Prime Minister Boris Johnson confirmed, as he thanked volunteers who made the results possible.

Health Secretary Matt Hancock said the NHS stands ready to roll out the vaccine if it is approved, which he said would provide a “significant boost to our vaccination programme and another weapon in our arsenal to beat this awful virus”.

The jab is expected to be available in the second half of this year if it receives MHRA approval – the UK has secured access to 60 million doses.

Where will it be produced?

The vaccine has been produced by Novavax, an American vaccine development company headquartered in Maryland. The company was founded in 1987, and focused principally on experimental vaccine development.

However, the jab will be physically manufactured in Teeside.

Stan Erck, chief executive of Novavax, told the BBC the manufacturing plant in Stockton-on-Tees should be up and running by March or April, with the company hoping to get approval for the vaccine from the MHRA around the same time.

Kate Bingham, the former chairwoman of the UK Government’s Vaccine Taskforce, told the BBC: “The Novavax vaccine is effective against the UK variant as well as the South African variant and has shown phenomenal efficacy, and it’s made in Teesside.

“So not only have we trialled the vaccine to show it is safe and effective, but we are also making it too. So we will be able to save lives in the UK.”

Novavax vaccine: where is it being made, who owns it - and when might it be used in the UK?