Oxford Covid-19 vaccine Q&A: How effective is it, and how is it different to the Pfizer vaccine?

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The coronavirus vaccine rollout is in full flight in the UK, and ministers say they are on track to fulfil Boris Johnson’s pledge to have offered a vaccination to everyone in the top four priority groups by Feb 15.

That target could be met as soon as Saturday. On Friday night, Boris Johnson said 14 million people had received their first jab and that “it looks like we are on target to have vaccinated the most vulnerable groups” by Feb 15.

However, speaking in a video posted to Twitter, the Prime Minister urged the “few people, a million or more, who have not come forward to get your vaccinations in this group” to do so.

As of Feb 15, more than 15 million people in the UK have had at least one Covid vaccine since the programme was launched – amounting to nearly one in five adults – while more than 545,000 of those have received a second dose.

Almost 90 per cent of people aged 80 and over have been vaccinated in England. Vaccinations have now begun in priority groups three and four, which includes those in their 70s – some 5.6 million people – and people listed as clinically extremely vulnerable.

On Feb 5, it emerged that England and Wales are hoping to have vaccinated all over-50s by early May.

The Pfizer/BioNTech vaccine and Oxford/AstraZeneca vaccine are the two jabs currently in rotation in the UK, with doses developed by Moderna, which was approved on Jan 8, expected to arrive by spring. New results on Feb 2 showed that a single dose of the Oxford-AstraZeneca vaccine prevents two-thirds of Covid transmissions, raising hopes for the easing of restrictions by Easter.

Lockdown timeline: How Boris Johnson’s roadmap to lifting restrictions might look

The UK could also soon approve the Novavax vaccine as results show it was 89 per cent effective in large-scale trials.

How does the AstraZeneca/Oxford vaccine work?

The vaccine – called ChAdOx1 nCoV-19 – uses a harmless, weakened version of a common virus that causes colds in chimpanzees.

Researchers have already used this technology to produce vaccines against a number of pathogens including flu, Zika and Middle East Respiratory Syndrome (Mers). The virus is genetically modified so it is impossible for it to grow in humans.

Scientists have transferred the genetic instructions for coronavirus’s specific ‘spike protein’ – which it needs to invade cells – to the vaccine.

When the vaccine enters cells inside the body, it uses this genetic code to produce the surface spike protein of the coronavirus. This induces an immune response, priming the immune system to attack coronavirus if it infects the body.

How effective is it?

Oxford University and AstraZeneca – a British-Swedish multinational pharmaceutical and biopharmaceutical company with its headquarters in Cambridge – announced that their jab was effective in preventing many people getting ill and it has been shown to work in different age groups, including the elderly.

Partial immunity against Sars-Cov-2 is then detected approximately 22 days after administration of the first dose, the MHRA reported.

Data published in The Lancet in early December showed the vaccine was 62 per cent effective in preventing Covid-19 among a group of 4,440 people given two standard doses of the vaccine, when compared with 4,455 people given a placebo drug. The overall Lancet data, which was peer-reviewed, set out full results from clinical trials of more than 20,000 people.

Among the people given the placebo drug, 10 were admitted to hospital with coronavirus, including two with severe Covid-19 which resulted in one death. However, among those receiving the vaccine, there were no hospital admissions or severe cases. The combined analysis from both dosing regimens resulted in an average efficacy of 70.4 per cent.

According to new results, a single dose of the Oxford-AstraZeneca vaccine prevents two-thirds of Covid transmissions, raising hopes for the easing of restrictions by Easter.

The data, released on Feb 2, also revealed that the first jab prevents 100 per cent of hospitalisations after 22 days once an immune response has had time to develop.

The study found a single dose was 76 per cent effective in fending off infection between 22 days and 90 days post-injection, rising to 82.4 per cent after a second dose at that stage.

In a major vindication of government policy, the study also found that the vaccine is more effective overall if the second dose is delayed from 28 days until 90 days.

Is it effective against the new variants?

Data on the highly contagious Covid-19 variant identified in England do not suggest that the AstraZeneca / Oxford vaccines will be less effective against it.

“We have the most data on the UK variant. That doesn’t suggest that it will be any less well protected against by the vaccine,” said Wei Shen Lim, chair of Covid-19 Immunisation on Britain’s Joint Committee on Vaccination and Immunisation, on Jan 13.

The Oxford University researchers who developed the jab say it has a similar efficacy against the variant compared to the original Covid-19 strain it was tested against.

Professor Andrew Pollard, a chief investigator on the Oxford vaccine trial, said new data suggests “the vaccine not only protects against the original pandemic virus, but also protects against the novel variant, B.1.1.7”.

But research has revealed that the Oxford vaccine “provides minimal protection” against mild disease caused by the variant of Covid-19 first discovered in South Africa, according to early data from a small trial.

A study suggested the Oxford vaccine was only 10 per cent effective against the variant.

The study, from South Africa’s University of the Witwatersrand and Oxford University, analysed the E484K mutation in some 2,000 people, most of whom were young and healthy.

The team found that the vaccine had “substantially reduced” efficacy against the South African variant compared to the original strain of Sars-Cov-2.

South African authorities suspended the country’s vaccination programme on Monday 8 Feb following this discovery, stating more research is needed.

Professor Salim Abdool Karim, leader of South Africa’s Covid response, said: “We don’t want to end up with a situation where we vaccinate a million people or two million people with a vaccine that may not be effective at preventing hospitalisation and severe disease.”

However, scientists advising the World Health Organization warned against jumping to conclusions and actually awarded emergency-use licenses to two versions of the Oxford-AstraZeneca jab on Monday 15 February.

Many experts have pointed out that the study on the South African variant was small. While it looked into whether the vaccine prevents mild and moderate disease in a group of mostly young people, it did not look at whether the vaccine prevents severe disease, hospitalisation and deaths.

Sarah Gilbert, professor of vaccinology at the University of Oxford, told the BBC she was confident the vaccine would prevent severe illness.

However, a tweaked Oxford vaccine which can cope with the new coronavirus variants circulating in Britain will be trialled in the coming months before being rolled out in the the autumn, scientists have said. And the World Health Organization looks set to approve the Oxford-AstraZeneca vaccine for use in developing countries.

Moderna and Pfizer-BioNTech both said their vaccines were effective against new variants of the coronavirus discovered in Britain and South Africa, but they are slightly less protective against the variant in South Africa, which may be more adept at dodging antibodies in the bloodstream.

As a precaution, Moderna has begun developing a new form of its vaccine that could be used as a booster shot against the variant in South Africa.

It was also announced on Feb 5 that the UK Government has struck a deal with the German drugs firm CureVac for 50million doses of vaccine designed to beat future variants.

How is the rollout going?

The Oxford vaccine rollout began on Jan 4 at the Oxford University Hospitals NHS Foundation Trust’s Churchill Hospital.

Mr Johnson has said the NHS is committed to offering a vaccination to everyone in the top four priority groups by Feb 15 – the Government are currently on target to achieve this.

The government also revealed on Feb 5, that all adults aged 50 and over will have been offered the coronavirus vaccine by early May.

As of Feb 7, more than 12 million people in the UK have had at least one dose of a Covid vaccine, this is equivalent to one in five adults.

Britain’s daily vaccination rate hit a new record high on Jan 31, with almost 600,000 receiving their first dose of the vaccine within a day.

The number of doses administered daily throughout the UK reached a seven-day average of 400,000, as of Feb 3.

Vaccine minister Nadhim Zahawi announced on Feb 4, the opening of 39 new vaccine sites and 62 more pharmacy-led sites to make “vaccinating the most vulnerable even quicker and even simpler”.

There are now 89 large vaccination centres and 194 sites run by high street pharmacies, along with 1,000 GP-led surgeries and more than 250 hospital hubs across the country administering vaccines.

What has Germany said about the vaccine?

The vaccine was approved for adults in the EU on Jan 29.

This news follows a draft recommendation from Germany’s vaccine authorities called for its use to be restricted to those aged between 18 and 64.

“There is currently insufficient data to assess the effectiveness of the vaccine from 65 years of age,” the Standing Vaccine Commission (Stiko) at the Robert Koch Institute, Germany’s main centre for disease control, said.

The German recommendation was issued by an independent panel of doctors and scientists, who released detailed figures to back their findings.

They did not conclude the vaccine is ineffective in older people, but only that clinical trials had simply not included enough test subjects aged over 65 to provide any reliable data.

Denmark, Norway, France and Sweden are the latest European countries not to offer the AstraZeneca vaccine to individuals over the age of 65, citing a lack of data, while Poland has said the vaccine will only be used for people aged 18-60.

However, the European medicines regulator approved the vaccine, stating its belief that the AstraZeneca jab was suitable for older people – a message that was later echoed by WHO scientists.

Public Health England has defended the Oxford vaccine as safe and effective for older people. Boris Johnson also jumped in to highlight that the evidence shows the jab “provides a good immune response across all age groups”, after German regulators proposed to block its use in the elderly.

The UK remains confident that the vaccine is effective for over 65s, Munir Pirmohamed told a MHRA news briefing.

“Since (initial approval) we’ve seen more data coming through from AstraZeneca as more people are completing the trial, which highlights again that efficacy in the elderly is seen, and there’s no evidence of lack of efficacy,” he said.

The Medicines and Healthcare products Regulatory Agency (MHRA) said its analysis showed a reporting rate of three suspected side-effects for every 1,000 doses of vaccine administered – with the issues reported being similar to those for the annual flu vaccine.

Dr June Raine, chief executive of the MHRA, said: “Vaccines are the most effective way to protect against Covid-19 and save lives and prevent serious complications from this terrible virus.

“The data we have collected provides further reassurance that the Covid-19 vaccines are safe and continue to meet the rigorous regulatory standards required for all vaccines.

“We remain confident that the benefits of these vaccines outweigh any risks.”

Read more: German response to Oxford vaccine is unfair blow for UK scientists and will cause needless worry

Why was the EU arguing with the UK over vaccine exports?

The European Union and the UK were embroiled in a row over vaccine exports after the EU demanded access to AstraZenca vaccines that were being manufactured in the UK.

This demand by the EU was an attempt to make up for a shortfall in their supply after the British-Swedish pharmaceutical company said it could only supply a quarter of the jabs – 31 million instead of the initial 80 million it had aimed for in the first quarter of the year.

While Britain used emergency procedures to grant market approval to the AstraZeneca vaccine, and signed a contract with the company three months before Brussels, the EU used a slower process overseen by the European Medicines Agency.

The contract between the EU and AstraZenca that was agreed in August 2020 revealed that the two sides agreed manufacturing sites “shall include the United Kingdom” – adding weight to the EU’s position. It also stipulates that other deals cannot supercede any agreement with the EU.

Brussels accused AstraZeneca of breaching its contract and, amid suspicions it had supplied EU vaccine stock to the UK, launched plans to force all EU vaccine manufacturers to ask for permission before exporting jabs out of the bloc.

On Jan 29, the President of the European Commission, Ursula von der Leyen, took the controversial decision to invoke Article 16 of the Northern Ireland Protocol to prevent the protocol from being used as a “back door” to bypass restrictions the EU had placed on vaccine exports from leaving the bloc.

The First Minister of Northern Ireland, Arlene Foster, described the move as an “incredible act of hostility”, whilst the Prime Minister, Boris Johnson, expressed “grave concerns” over the EU’s decision and called Irish Prime Minister, Micheal Martin. Mr Martin said that he had no prior knowledge that the EU intended to invoke Article 16 and initially heard about it through a public statement.

Just hours later, a U-turn came from the EU where they said that the decision to trigger Article 16 was an “oversight”, after widespread condemnation from leaders over the move.

Ms von der Leyen later tweeted that she had spoken to Mr Martin and had “constructive talks” with Mr Johnson.

Although, Ms von der Leyen admitted the move was an error, she has refused to take personal responsibility for the mistake.

AstraZenca has now agreed to supply the EU with nine million additional vaccines by the end of March, Ms von der Leyen called the gesture “a step forward”.

Read more: Ursula von der Leyen accidentally makes the case for Brexit as she tries to explain EU vaccine delays

How many doses does the UK have?

The UK has secured 100 million doses of the Oxford/AstraZeneca vaccine, this is the most the Government has ordered out of all of the potential vaccine candidates. The order is enough to vaccinate 50 million people.

AstraZeneca said it aimed to supply millions of doses in the first quarter of this year as part of an agreement with the Government. There will be four million doses available post-authorisation and tens of millions of doses in the first quarter of this year.

A specific schedule is difficult to establish as batches need to be quality approved by the MHRA.

Does it differ to Pfizer and Moderna’s vaccines?

Yes. The jabs from Pfizer and Moderna are messenger RNA (mRNA) vaccines.

Conventional vaccines are produced using weakened forms of the virus, but mRNAs use only the virus’s genetic code.

An mRNA vaccine is injected into the body where it enters cells and tells them to create antigens.

These antigens are recognised by the immune system and prepare it to fight coronavirus.

No virus is needed to create an mRNA vaccine. This means the rate at which the vaccine can be produced is accelerated.

The Pfizer and Moderna vaccines have both been approved in the US.

The UK Government began the roll-out of the Pfizer vaccine on Dec 8.

Unlike the Pfizer vaccine, the Oxford jab does not require ultra-low temperatures.

The Oxford jab requires temperatures between 2C and 8C and can be stored for at least six months.

This is the typical temperature of a domestic refrigerator and this will make deployment of the vaccine much easier and faster.

What about antibodies and T-cells?

The Pfizer, Oxford/AstraZeneca and Moderna vaccines have been shown to provoke both an antibody and T-cell response.

Antibodies are proteins that bind to the body’s foreign invaders and tell the immune system it needs to take action.

T-cells are a type of white blood cell which hunt down infected cells in the body and destroy them.

Nearly all effective vaccines induce both responses.

The Oxford/AstraZeneca vaccine induces robust antibody and T-cell responses across people of all ages, the data indicates.

Can the Oxford vaccine be manufactured to scale?

Yes. The UK Government has secured 100 million doses as part of its contract, enough for most of the population.

The head of the UK Vaccine Taskforce, venture capitalist Kate Bingham, has said she is confident it can be produced at scale.

Where is it being manufactured?

While there are some doses coming from Europe in the very first instance, the majority will be provided from the UK supply chain.

In an exclusive report on Jan 16, The Telegraph shared plans for a new £158m “super-factory”, which would produce 70m doses of an emergency vaccine on British soil- enough to vaccinate the entire nation against new coronavirus strains within four months. The factory will open later this year.

Do you need two doses of the Oxford vaccine?

The MHRA has recommended the over-18s should receive two doses to be administered with an interval of between four and 12 weeks.

When will I get my second dose?

The Government announced on Dec 30 that it was delaying the second dose of every vaccine in order to reach as many people as possible in the first round of vaccinations.

Both the Oxford vaccine and the Pfizer/BioNTech jab will be given to people as one shot, followed by another up to 12 weeks later, in order to extend some protection to as many people as possible as quickly as possible.

This is not without controversy, however.

The government’s Joint Committee on Vaccination and Immunisation (JCVI) says unpublished data suggests the Oxford-AstraZeneca vaccine is still effective with doses 12 weeks apart – but Pfizer has said it has tested its vaccine’s efficacy only when the two doses were given up to 21 days apart.

The World Health Organization has recommended a gap of four weeks between doses – to be extended only in exceptional circumstances to six weeks.

Will the vaccines be given out 24 hours a day?

In a further bid to accelerate vaccination, Boris Johnson has announced that 24-hour vaccine centres will be opened “as soon as we can”, with the the head of NHS England confirming on Jan 17 that several hospitals will trial 24/7 vaccine centres within the next ten days.

Matt Hancock, however, told BBC Breakfast a 24/7 approach was unlikely to be “the major factor” in hitting the mid-February target, but he was “absolutely” behind it “if it helps speed things up”.

Sources in Whitehall have said that plans are in place to pilot a 24-hour vaccination centre to test demand. This comes as manufacturing companies have told ministers that they will not yet be able to produce enough vaccines should 24-hour roll out be introduced across the country.

Supplying vaccinations overnight will speed up the rollout, and allow the Government to reach their goal of vaccinating 32 million people- 60 per cent of the UK adult population by Spring-which was announced on Jan 11.

Can this vaccine help the elderly?

There have been concerns that a Covid-19 vaccine will not work as well on elderly people, much like the annual flu jab.

However, data from the Oxford/AstraZeneca trial suggests there have been “similar” immune responses among younger and older adults.

The results show that the vaccine is better tolerated in older people compared with younger adults, and produces a similar immune response in old and young adults.

Can pregnant women have the vaccine?

Pregnant women and breastfeeding mothers have now been given the green light to take either the Oxford and Pfizer coronavirus vaccines following an appropriate case-by-case risk evaluation with their healthcare practitioner.

This is a reversal of previous advice which was put in place as precautionary measure.

Traditionally pregnant women are not included in clinical trials, but following a review the MHRA are recommending pregnant women be given the opportunity to receive the vaccine as as there is no evidence they would be at risk.

Dr June Raine, chief executive of the MHRA, said: “Our advice to date has been that given that in initial lack of evidence on a precautionary basis, use of a vaccine wasn’t recommended in pregnancy and women with breastfeeding should not be given the vaccine.

“But now that we have reviewed further data that has become available, the Commission on Human medicines has advised that the vaccine can be considered for use in pregnancy when the potential benefits outweigh the risks following an individual discussion with every woman.”

Can people with allergies have the vaccine?

The rollout of the Pfizer vaccine was temporarily halted for those who are known to suffer from severe allergic reactions following a handful of adverse events in the initial distribution of the vaccine.

There were some concerns that this would also apply to the Oxford jab.

However, following a review, the UK regulatory body has recommended both the Pfizer and Oxford vaccine are safe to administer to those with food or medicine allergies.

Only those who have a known history of reacting to vaccines in the past should proceed with caution.

Sir Munir Pirmohamed, clinical pharmacologist and geneticist, and chairman of Commission on Human Medicine Expert Working Group, said. “We’ve come to the recommendation people with a known history of reacting to any specific ingredients of vaccine should not have it. But people with allergies to other medicines or food can have the vaccine.”

Dr June Raine added that “at least 800,000 in the UK, probably a million and a half in the US” have already received the Pfizer vaccine.

There has been “no additional concerns and this gives us further assurance that the risk of anaphylaxis can be managed through standard clinical guidance and an observation period following vaccination of at least 15 minutes.

Read more: The priority list for the Oxford and Pfizer vaccines – and how they will be rolled out

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