It is the first jab to be a “whole inactivated virus”, which is a traditional approach that has been used for decades to make vaccines for other diseases, including polio and flu.

This approach is less effective at making specific antibodies than the existing jabs, but scientists think it may give more well-rounded protection and be superior at combating any future variants.

The virus is grown in a lab and completely neutralised so that it cannot infect cells or replicate in the body, but can still trigger an immune response.

UK has not bought any Valneva doses

Yet while the MHRA has found the French-made jab to be sufficiently safe and effective as a first and second dose in people aged 18 to 50, the UK has not bought a single dose. It is also not approved as a booster.

The Government had previously ordered 60 million doses and then topped this up to 100 million in early 2021. The vaccines were set to be manufactured in Livingston, Scotland, which the Prime Minister visited at the time.

However, in September 2021, the contract was cancelled, with the Government citing a breach of contract.

Professor Adam Finn, a member of the JCVI and the chief investigator of Valneva’s clinical trials, told The Telegraph: “The implication, I think, was that [the Government] were saying that the expansion of the manufacturing plant in Scotland was not on track or not moving forward as fast as it was meant to have done, but the company actually denied that.

“I don’t know whether they’re in some kind of ongoing dispute over that, but that was what was suggested.

“MHRA approval is a step forward in terms of the use of the vaccine but not a very particularly big step forward in terms of its use in the UK, because the order for the vaccine was cancelled back in September.

“It’s not been approved yet as a booster anyway, so even if they had ordered it, they wouldn’t be able to use it as a booster at this point, because the approval is only for primary doses.

“The only people who theoretically could benefit from this vaccine at this time in the UK would be people who have not been vaccinated so far but want to be and are hesitant about the available vaccines.”

He added that the traditional and simple way of making the vaccine means Valneva’s manufacturing process could be replicated around the world at existing factories with relative ease. The green light from the notoriously stringent MHRA may also now open the floodgates for other regulatory bodies around the world to authorise the vaccine.

Decision due over European approval

Europe’s MHRA equivalent, the European Medicines Agency (EMA), is expected to make a decision next week, with Prof Finn optimistic.

Dr June Raine, MHRA chief executive, said on Thursday: “Our approval of the Covid-19 vaccine made by Valneva today follows a rigorous review of the safety, quality and effectiveness of this vaccine, and expert advice from the Government’s independent scientific advisory body, the Commission on Human Medicines.”

Professor Sir Munir Pirmohamed, chairman of the independent Commission on Human Medicines, added: “Each type of vaccine has a different pattern of antibody response over time.

“For the Valneva vaccine, two doses are required before a robust antibody response is raised. This means that people will need to be made aware that protection will only start after two doses.

“The storage temperature for the Valneva vaccine – of 35.6F (2C) to 46.4F (8C) – is similar to that of a domestic fridge, making it appropriate for use in countries where storage at very low temperatures is not possible.”