Covid vaccine: Everything we know about the Oxford jab

After months of waiting and speculation, Oxford University’s Covid vaccine has finally been approved for use by the UK’s drugs regulator.

It’s a moment that couldn’t have come sooner, with the NHS once again pushed to the brink following a surge in cases and hospitalisations across the four nations. 

Health officials and local authorities will now begin rapidly administering the two-dose vaccine, described as a “game-changer” by experts, as the government aims to bring the pandemic under control by spring.

What does the data show?

Results taken from the vaccine’s large-scale trials in the UK and Brazil show that it is safe and highly effective.

To date, no cases of hospitalisation or severe disease have yet to be reported among volunteers who received the vaccine.

It is not currently known how long the jab provides protection for. This will take time and further analysis to determine.

Similarly, it is also unclear whether the vaccine can halt transmission of the virus – but early indications suggest it may have an effect.

When will it be available?

As soon as possible. The government is aiming for 4 January, and is optimistic that more than 2 million vulnerable people could receive their first dose by mid-January.

Across the four nations, work has been underway to transform football stadiums, conference centres and racecourses into mass vaccination centres. These sites will be crucial for a rapid rollout that will eventually allow up to two million people a week to receive the jab.

Pascal Soriot, chief executive of AstraZeneca, said the manufacturer would be able to provide one million doses and beyond per week.

How will it be administered?

People receiving the Oxford vaccine or the Pfizer-BioNTech candidate, which was approved earlier this month, will be injected with their first dose followed by a booster jab up to 12 weeks later, the Joint Committee on Vaccination and Immunisation (JCVI) said on Wednesday.

The aim is to give as many people as possible a first dose of a Covid-19 vaccine, rather than reserving initial supplies for a second jab.

The Department of Health and Social Care said: “Having studied evidence on both the Pfizer-BioNTech and Oxford-AstraZeneca vaccines, the JCVI has advised the priority should be to give as many people in at-risk groups their first dose, rather than providing the required two doses in as short a time as possible.

“Everyone will still receive their second dose and this will be within 12 weeks of their first. The second dose completes the course and is important for longer term protection.” 

Professor Wei Shen Lim, chair of the JCVI, said this “will allow the greatest number of people to receive the vaccine in the shortest possible time – and that will protect the greatest number of lives”. 

In a joint statement, the chief medical officers of the four nations of the UK said they agreed with the JCVI that first doses should be prioritised.

How many doses does the UK have?

Downing Street has thrown much of its support and financial weight behind the Oxford vaccine, securing a total of 100 million doses – the largest pre-order in its portfolio.

The government missed its target of producing 30 million doses by September, the UK’s vaccine taskforce chief admitted last month. At the time, Kate Bingham said she expected there to be 4 million doses available by the end of the year – yet Matt Hancock said on Wednesday this figure stood at 530,000.

The UK has reached agreements with seven different vaccine manufacturers for a total of 357 million doses.

Approval has already been granted for the Pfizer-BioNTech vaccine, with up to 40 million doses of this candidate set to be delivered by the end of next year.

What are the logistics behind the Oxford vaccine?

Unlike its rivals, the jab can be kept at fridge temperature (2-8C) for long periods of time, meaning authorities aren’t facing the arduous task of storing and transporting it in sub-zero conditions.

GP surgeries will be able to keep vials of the vaccine in their fridges, batches can be easily split up and sent into care homes, and there won’t be as much of a rush to get through supplies to prevent them from spoiling.

All of these advantages will ensure that the vaccine can be distributed and administrated at a much quicker rate than alternative candidates.

This will also ensure that poorer countries that do not have widespread sub-zero refrigeration capacity will be able to access and use the vaccine.

How much will it cost?

Details of pricing haven’t been formally released but there are various figures in the public domain which point to a low cost.

The deal struck between the European Union and AstraZeneca has priced the vaccine at £2.23 per dose.

Although the UK government has yet to disclose the full details of its own deal with the pharmaceutical, it’s thought the NHS will be paying similar prices.

Importantly, AstraZeneca has agreed to make the vaccine on a not-for-profit basis for the duration of the pandemic. It has also pledged to sell it at cost to developing nations in perpetuity.

In contrast, two doses of the Pfizer-BioNTech jab cost £29.50 for Americans.

Where will the vaccine be made?

The initial rollout of the Oxford vaccine in Britain will use doses manufactured in Europe, according to the UK’s Vaccine Taskforce.

Ian McCubbin, manufacturing lead for the taskforce, said earlier this month the “vast, vast majority” of the 100 million doses of the drug ordered by the UK from AstraZeneca will be made in the UK.

However, the first wave of supplies have actually been made in the Netherlands and Germany, Mr McCubbin said.

What’s the technology behind the vaccine?

The Oxford candidate is different to the mRNA platforms that form the basis of the Moderna and Pfizer-BioNTech vaccines.

Developed by Sarah Gilbert, a professor of vaccinology at Oxford University, AZD1222 uses an engineered viral vector to train the body in neutralising any future infection from Sars-Cov-2 – the virus that causes Covid-19.

Conventional vaccines are made by weakened viruses or by purifying parts of the pathogen – such as the so-called “spike” protein, which is responsible for attaching to human cells. But these methods can take decades to develop new vaccines.

Instead of making weaker viruses, or delivering mRNA, as Moderna and Pfizer did, the Oxford vaccine packages the DNA codes for the spike protein of Sars-Cov-2 into a genetically-altered chimpanzee virus.

The original adenovirus causes the common cold in chimpanzees and it rarely, if ever, infects humans. The virus is further modified to ensure it cannot grow in people. The AstraZeneca vaccine uses this modified pathogen as a vehicle to deliver the spike protein of the Sars-Cov-2 virus, which is then expressed by the body’s cells.

The immune system responds accordingly and creates the necessary antibodies and T-cells that will provide protection against any exposure to the real virus.

Will the vaccine be effective against the new coronavirus variant?

All current evidence suggests the vaccine, along with other candidates, will remain effective.

It’s true that the vast majority of vaccines in development target the spike receptor of the virus. If it changes beyond recognition due to mutations, the jabs may be unable to induce the necessary immune response within people.

However, the proteins that coat the shell of Sars-Cov-2 would need to undergo significant genetic transformations to render the vaccines redundant – something that, at this stage, doesn’t appear to have happened.

Of the 23 mutations identified in the new variant, only a handful concern the virus’s spike protein. Scientists have insisted there are many other components to its structure that will still be targeted by the antibodies and T-cells induced by the vaccines.

Pascal Sorio, AstraZeneca’s chief executive, said: “So far, we think the vaccine should remain effective. But we can’t be sure, so we’re going to test that.”

What about the controversy surrounding the trial data?

Although the Oxford vaccine has been heralded as a game-changer in the fight against Covid-19, its journey to authorisation has been mired by controversy and apparent irregularities in the trial data.

It was revealed last month that the half dose-full dose regime delivered an efficacy rate of 90 per cent in the UK trial.

But separate data showed that the vaccine was only 62 per cent effective when administered as two full doses. Scientists have yet to fully explain the discrepancy in results between the two dosing regimes.

Dr June Raine, chief executive of the Medicines and Healthcare products Regulatory Agency, said “extremely careful” consideration was paid to the different dosing regimes implemented during the large-scale trials and the points at which the second shots were administered.

In some subgroups of the trial, volunteers were given their follow-up jab 26 weeks after the first dose, the regulatory body said.

However, the MHRA settled upon the standard two full-dose programme over a three-month time frame as trial data for this regime was the “most robust”. It triggers an immune response that is 80 per cent effective at preventing the disease, according to trial data passed to the MHRA.

Questions were also raised over whether the vaccine had been tested on enough people over the age of 55 and was therefore capable of inducing protection among one of the most vulnerable groups.

Professor Sir Munir Pirmohamed, of the Commission on Human Medicines, said there was a “small amount of data available” which pointed to the effectiveness of the vaccine in the elderly.

“Older people have been recruited and more data and older people will be coming online in early 2021, not only from the UK trial but also from the trial in Brazil, but also the trial being undertaken in the United States,” he added.

How do other approved vaccines compare?

Both the Moderna and Pfizer-BioNTech vaccines, which make use of mRNA technology, have been shown to be around 95 per cent effective in preventing Covid-19.

There are no queries or complications surrounding the trial data for the two candidates, with each vaccine tested on a wide range of age and ethnic groups. 

Whereas the Oxford vaccines is cheap and affordable, making it accessible to some of the poorest governments in the world, its rivals have been priced at between £15 and £30.

These mRNA vaccines are also more difficult to store. They must be kept at sub-zero temperatures and cannot be easily transported between locations. The Oxford jab, in contrast, can be kept at 2-8C for up to six months.

The Pfizer-BioNTech vaccine was the first vaccine to achieve approval in the world and has since been licensed for use in a number of countries. The Moderna jab has only been given the green light in America.