Johnson and Johnson vaccine: efficacy of the single-shot vaccine, how does it work and has it got UK approval?

A vaccine produced by Johnson and Johnson could be rolled out in the US from 1 March (Picture: Getty Images)

US medical company Johnson and Johnson has had its Covid vaccine confirmed as safe by the US Food and Drug Administration (FDA).

Trials have shown the vaccine is more than 60 percent effective in preventing moderate illness, and could be a more cost-effective vaccine than US-competitors Pfizer and Moderna.

So, how did it fair in trials and will it become available in the UK? This is what we know so far.

What is the Johnson and Johnson vaccine?

The vaccine is cheaper than both the Pfizer and Moderna vaccines, and can be stored in a refrigerator instead of a freezer.

It is a single jab vaccine which has been proven to prevent serious illness by around 85 percent and moderate illness by 66 percent.

The vaccine was devised by Janssen, a pharmaceutical branch of Johnson and Johnson. The company is now looking at whether two jabs would lead to a greater immune response.

Dr Mathai Mammen, from Janssen, said: "A single dose regimen with fast onset of protection and ease of delivery and storage provides a potential solution to reaching as many people as possible.

"The ability to avoid hospitalisations and deaths would change the game in combating the pandemic."

The company has agreed to provide the US with 100 million doses by the end of June.

The White House has confirmed that if it is given approval by FDA on Friday, then three million doses will be offered to people in the US in the week commencing 1 March.

How does it compare to other vaccines?

The vaccine is largely similar to the Oxford-AstraZeneca vaccine in that it binds a dormant strain of Covid onto a common cold virus to be carried into the body without any risk of infection.

The body then produces an immune response to the coronavirus cells, building up immunity.

The vaccine differs from other vaccines in that the one dose will be more time effective and is easier to transport than the Pfizer vaccine as it does not require sub-zero temperatures.

In terms of effectiveness, it provides an overall average efficacy 76.5 percent, which is higher than the AstraZeneca vaccine, which offers an average efficacy of 70.4 percent.

Pfizer has proven to be 75 percent effective after the first dose.

Will it be available in the UK?

The UK, EU and Canada have now ordered doses and 500 million doses have also been ordered through the Covax scheme to supply poorer nations.

This comes as richer nations such as the UK pledge their spare doses to impoverished countries.

The UK is expected to administer 30 million doses. The EU has ordered 200 million doses, Canada has purchased 38 million doses and the US is to receive 100 million doses.

There has been no confirmation from The Medicines and Healthcare Products Regulatory Agency (MHRA) as to when it will be rolled out in the UK.