Britons will be the first people in the world to get a coronavirus vaccine but what exactly is the Pfizer jab, who will get it, and is it safe? Here we answer the big questions:
What we know
Who will get it first and why?
The Joint Committee on Vaccination and Immunisation (JCVI) initially said care home residents and staff should be first in line for the shots, followed by those aged over 80 and general health workers.
However the Pfizer/BioNtech jab must be shipped in dry ice at -103F (-75C) and only lasts for five days once stored in a fridge at usual temperatures of 35.6F – 46.4 (2-8C) so it is impractical to roll it out in care homes.
While the Government is insisting care homes will be targeted first, practically, that is unlikely to happen.
On December 2, Boris Johnson expanded more on how the vaccine would be implemented across care homes. He said: “Of course we want to get it into care homes as fast as we possibly can”. Though they are waiting to hear more, they are adamant that they will get it to “the most vulnerable”.
However, in the response criticism that the temperature of the vaccine would make it difficult to be issued around care homes, Professor Van-Tam argued that it was “extremely unfair when one considers a new virus emerged less than 12 months ago and we now have our first vaccine”.
Instead, it is expected only NHS staff will get the jab initially, and care homes may need to wait until the Oxford or Moderna vaccine is available before vaccinating residents and staff, as both can be stored at normal fridge temperatures.
NHS staff were told to get their winter flu jab by the end of November because there needs to be at least a week between the two vaccinations and NHS clinics have also been told to prepare for vaccinating their staff.
Senior NHS officials claim the jab can only be transported once more after it arrives at a central hub, and has to be moved in batches of 975 – meaning the vaccine will be wasted if it is sent to smaller care homes which have only a few dozen residents.
However Pfizer has said the jab can be sent to care homes, as long as the vaccine travels for no more than six hours after it leaves cold storage and is then put in a normal fridge at 2C to 8C. So expect arguments in the coming days over who gets the first doses.
At Wednesday evening’s press conference Sir Simon Stevens, the chief executive of the NHS, said care-home residents coming into hospital for outpatient appointments will still be able to access the jab.
When will the general population be allowed the jab?
After care homes, the JCVI has recommended the population be vaccinated in five-year groups starting with the over-75s.
The Joint Committee on Vaccination and Immunisation has also stated that key workers will be prioritised in the second phase of the vaccine roll out. Therefore, transport workers, first responders and teachers will be among the first to receive the jab after the most vulnerable.
Roughly one third of the population in Britain is over 50 and Britain has only secured 40 million doses of the Pfizer vaccine so it is unlikely that anyone in the general population will be included in the first round of immunisation.
Around 1.4 million people also work for the NHS, and they will also take priority.
If the Oxford vaccine is approved by regulators it may be possible to speed up the move to immunising greater numbers, but that is unlikely to happen before the Spring.
The Chief Executive of the National Health Service, Sir Simon Stevens also revealed more about who would receive the second doses, sharing they would be reserved for those getting the first dose in December.
Sir Simon shared: “We need to be very careful through December and into January and then as vaccination expands to the wider population”.
He went on to add that a phasing of delivery would involve 50 'hospital hubs’ which will offer the jab from the week beginning December 7 to the over-80s, care home staff and others identified by the Joint Committee on Vaccination and Immunisation.
The Chief Executive also said that patients are likely to be people who were scheduled to attend outpatient appointments, which will eventually be followed by over 1,000 vaccination centres over time.
Simon Stevens has said the bulk of the vaccination programme will take place in the January to April next year.
What plans is the NHS making to vaccinate the population?
Hospital hubs are being set up for NHS and care staff and older patients to get vaccinated and vaccination centres are being established across the country for when the mass vaccination programme begins.
The NHS has been preparing for a mass vaccination programme for several weeks with up to 1,500 GP practices and drive-through centres ordered to open from 8am to 8pm every day, each dispensing at least 1,000 jabs a week.
Under the current plans, local clusters of about five practices covering approximately 50,000 patients, known as Primary Care Networks, will combine to organise vaccine delivery and the NHS is hoping to immunise one million people per week.
It could mean transforming one surgery into a vaccine hub while moving the normal services usually performed there to neighbouring practices or hiring new premises altogether.
GPs have been told they can scale back other work as the vaccination programme takes precedence and will be paid £12.58 for each vaccine dose administered. Medical and nursing students, retired medics, pharmacists and vets are being drafted in to help manage the huge enterprise.
Pfizer has confirmed that people in the UK will not be able to bypass the NHS roll-out and buy the vaccine privately.
How does the vaccine work, and how is it administered?
The Pfizer vaccine is an entirely new kind of jab. While the Oxford vaccine uses an inactive cold virus to produce the coronavirus spike protein – the little stick on the outside of the virus which allows it to attach to human cells – the Pfizer vaccine carries ‘messenger RNA’ which instructs the body’s own cells to build the coronavirus spike protein.
Once the body starts producing these proteins, the immune system sees them as foreign, and initiates a T-cell and antibody response, priming it to fight off a real infection.
So, in effect, the cells of the body are turned into little coronavirus factories. Although it might sound alarming, it does not change DNA and it cannot be passed on to future generations.
Those who are vaccinated will receive a jab in the arm, and immunity begins to build from day 12. A booster shot is then given at day 21, and full immunity is achieved by day 28. So it will take a month from the first jab to be fully protected.
It means that even those immunised next week will not be completely protected until January.
Studies have shown the jab is 95 per cent effective and works in all age groups. It means that 19 out of 20 people who receive the jab will be protected.
It is unknown how long immunity will last for, but studies of people who have caught coronavirus show antibodies and T-cells last at least six months and probably longer.
At Wednesday evening's press conference, Jonathan Van-Tam, the Deputy Chief Medical Officer, said phase one of the rollout would eradicate 99 per cent of Covid-19 deaths.
Will it stop transmission?
It is unclear whether the Pfizer jab will stop transmission of the virus as the trials did not look at that aspect. It could be several months before it is known whether it will stop people infecting others, although there is early evidence suggesting the Oxford vaccine does this.
If it does prevent transmission there will be a greater argument for vaccinating large numbers of the population to reach herd immunity. If not, it may be better to immunise those most at risk.
How hard is distribution?
The main drawback with thePfizer/BioNtech jab is that it must be shipped in dry ice. The company has designed special containers which keep the vaccine secure and track the temperature using special GPS sensors to make sure it does not get too warm on its journey.
The time between approval and deployment is expected to take roughly a week, due to travel and extensive safety and quality control checks so the first vaccinations will take place next week.
The vaccine is made in Belgium, and Health Secretary Matt Hancock has said that the doses will be rolled out as quickly as they can be made. So far the UK has 800,000 vaccines and approximately 10 million are expected by the end of the year.
Once dispatched from Belgium, the vaccine must follow a quality-assurance process to ensure nothing has happened in transit. Once cleared, the NHS can order it and will be delivered within 48 hours.
Defrosting the vaccine takes a few hours and then additional time is required to prepare the vaccine for administering.
How did Britain get it first?
There are more than 100 vaccines in production around the world, but Britain took a gamble on the seven most promising and fortunately the Pfizer/BioNTech jab was the first to release successful results.
Britain also has contracts with Oxford/AstraZeneca for 100 million doses of its vaccine, with Moderna for 7 million of its doses, with GlaxoSmithKline and Sanofi Pasteur for 60 million doses, with Novavax for 60 million doses,with Janssen for 30 million doses and with Valneva for 60 million doses.
However, it is the speed of the regulator that has allowed Britain to jump to the front of the queue.
In spite of Brexit, until the end of December, vaccines must still be authorised via the European Medicines Agency (EMA) and that authorisation will automatically be valid in the UK.
However, under a new regulation the Medicines and Healthcare products Regulatory Agency (MHRA) is allowed to temporarily authorise vaccine candidate if there is strong evidence of safety quality and effectiveness
The MHRA has been conducting rolling reviews of the vaccine trials, assessing safety along the way so could make a decision far more quickly. It means Britain will get the US/German jab before America or Germany.
Was it rushed through – don't vaccines normally take years?
The vaccine has indeed been produced at an unprecedented speed. While most vaccines normally take around a decade, the coronavirus jab has made it from the drawing board and into people’s arms in just 10 months.
The head of the MHRA, Dr June Raine, said that – in spite of the speed of approval – no corners have been cut.
Batches of the vaccine will be tested in labs "so that every single vaccine that goes out meets the same high standards of safety", she said on Wednesday.
Most of the side effects are very mild, similar to the side effects after any other vaccine such as muscle aches, headaches, soreness at the injection site and fatigue. They usually vanish after a couple of days.
Extreme reactions to vaccines usually occur very quickly after vaccination, and those getting the jab will be required to wait 15 minutes after immunisation to make sure there are no sudden side effects. The NHS will also be monitoring those vaccinated and any problems will be flagged early.
However, on Wednesday the European Medicines Agency (EMA), criticised the speed of British regulation and said its own longer approval procedure was more appropriate. The agency said it would not take a decision on the vaccine until December 29.
When will the other vaccines be ready?
The Oxford/AstraZeneca vaccine reported successful results last week and the MHRA is currently deciding whether to approve the jab. Approval is likely to come before Christmas. Britain is expecting to take delivery of 4 million doses before the end of the year.
On Monday, Moderna became the third vaccine producer to seek approval for its jab, which is also a messenger RNA vaccine similar to Pfizer's. The company has said it is keeping most of its stock for the US, so supplies are unlikely to arrive in Britain before the Spring.
US company Novovax is currently in phase three trials of its vaccine in the UK, which is expected to be available by mid-2021 while Jansen also recently began phase three clinical trial of a two-dose regimen of the vaccine, which includes UK volunteers. The UK Government has said it expects this vaccine to be available by mid-2021 if it is approved.
Sanofi and GSK started their phase one and two clinical trials in September and hope to move into a phase three trial before the end of the year.
Valneva's vaccine, which will be produced in West Lothian, in Scotland, is expected to enter clinical trials by the end of the year, and approval is not likely before next summer.
Is Pfizer safe for pregnant women?
The Joint Committee on Vaccination and Immunisation has announced pregnant women will not receive the jab, as the potential risks remain unknown. At present, there is a "lack of evidence"; though the research is still ongoing.
The official advice states: "Data on vaccine impact on transmission, along with data on vaccine safety and effectiveness, will potentially allow for consideration of vaccination across the rest of the population. As trials in children and pregnant women are completed, we will also gain a better understanding of the safety and effectiveness of the vaccines in these persons."
What we don’t know
How often will the vaccine be required?
At the moment it is unclear how long immunity lasts for. Early studies suggested antibodies wane very quickly in people who have been infected with coronavirus and there have been reports of people getting the disease for a second time.
However more recent evidence suggests that T-cells, a separate part of the immune system, may last longer.
In Severe acute respiratory syndrome (Sars), T-cells can remain active for up to 17 years. The government will be hoping that immunisation will last for at least a year.
Will those vaccinated be exempt from self-isolation or social distancing?
On Tuesday, Minister for the Cabinet Office, Michael Gove said there are no plans to introduce a ‘vaccine passport’ which would give people access to places such as pubs and restaurants once a coronavirus jab becomes available.
However, Parliamentary Under Secretary of State at the Department of Health and Social Care, Nadhim Zahawi, has said the Government is "looking at the technology" and hinted some venues would not allow people in without confirmation they had been immunised.
The Government is unlikely to consider vaccine passports until the jab is available to the wider population.
Will being in a higher tier mean you get the vaccine sooner than those in Tier 1?
At present, it appears the tier system will not influence who gets the jab. Those most at risk from all areas will be prioritised first.