BBC News 3 December 2020 - by James Gallagher
The Pfizer/BioNTech coronavirus vaccine has been approved for widespread use in the UK.
British regulator, the MHRA, says the jab is safe to start being used from next week.
What is the Pfizer vaccine and how does it work?
The vaccine trains the immune system to fight coronavirus.
The genetic material is encased in a tiny protective bubble of fat to get it into cells.
The exact ingredients of the vaccine have not been made public, but other vaccines can contain other ingredients, like aluminium, to make them stable or more effective.
The vaccine is given in two doses - three weeks apart - and offers up to 95% protection against Covid-19.
Has this type of vaccine ever been used before?
This is the first RNA vaccine to be approved for use in humans.
The concept has been researched before and people have been given them in clinical trials for other diseases.
The vaccine will be considered by regulatory agencies around the world, who will decide whether the jab can be approved for use.
Who will get it first and how soon can I have it?
In the UK, older care home residents and their carers are top of the priority list in the first phase of the vaccination programme. They are followed by frontline health and social care workers and the over-80s.
Out of the nine priority groups, those aged 50-54 are at the bottom of the current list.
The first jabs may take place within days now approval has been given.
There will be a second phase, which will offer the vaccine to the other groups in the population.
The vaccine will be delivered through care homes, GPs and pharmacists as well as "go-to" vaccination centres set up in venues like sports halls.
However, there are logistical challenges to overcome:
- It must be kept at -70C during transportation
- The jab must be thawed before it is given to a patient
- It can be stored in a normal fridge for a few days before being used
Will it offer lasting protection?
It is impossible to know and we will find out only by waiting.
If immunity does not last then it may be necessary to have annual vaccines, as we do for flu.
The vaccine appears to protect 94% of adults over 65 years old and data from its phase three trial suggests it works equally well in people of all ages and ethnicities.
Some people - such as those with a weak immune system - will not be able to have the vaccine.
Could the vaccine have long-term side effects?
Nothing in medicine is 100% safe - even something we take without thinking, like paracetamol, poses risks.
The data so far is reassuring - trials on 43,500 people discovered no safety concerns, although mild side effects, such as headaches and muscle aches, have been reported.
If there were highly dangerous and common consequences of this vaccination, they should have become apparent.
However, rarer side effects may emerge as millions of people are immunised.
Hopefully yes, but not for some time.
If enough people are immune then the virus would stop spreading and we would not need other measures.
However, the manufacture and distribution of a vaccine will take some time.
So testing, lockdowns, social distancing, and mask wearing are going to be a feature of our lives for a while yet.
Why can it only be made by Pfizer?
The vaccine has been designed and developed by Pfizer and BioNtech, and they own the intellectual property.
They already have the manufacturing capacity to produce 1.3 billion doses by the end of next year, but could partner with others to increase capacity even further.
What do we still need to know about the vaccine?
The announcement gave us the headline, but there is a still lack of fine detail.
We do not know if the vaccine stops you catching and spreading the virus or just stops you from getting ill. We also don't know how protective the vaccine is in different age groups.
These will be crucial for understanding how it will be used.
What does this mean for other vaccines?
It is good news - it shows that a coronavirus vaccine is possible,.
About a dozen vaccines are in the final development stages and those produced by Oxford University/AstraZeneca and Moderna have also proved successful in trials. The UK has ordered supplies of both.
