The UK became the first country in the world to begin distributing the covid-19 vaccine with "clinical approval" after Pfizer's bionetek vaccine received regulatory approval on Wednesday morning.
Clinical trial results show that the vaccine is 95 percent effective for all age groups.
But what does that mean for individuals in the UK, and when they can expect to get the vaccine?
What is expected in the UK?
The government has secured 40 million doses of Pfizer - biontik vaccine and 10 million of them are expected to be available in the UK by the end of the year.
Patients need two doses, that is, not enough doses are safe for the entire population of the UK.
How will the vaccine be distributed?
Work is under way behind the scenes to ensure that NHS staff are ready to start giving injections to the most vulnerable, as well as health and care workers, as a priority.
It was also decided that Nightingale hospitals, affiliated to the National Health Service, would be mass vaccination clinics - to their other uses.
In addition, FDA officials spoke of "mobile teams" that will be deployed to provide the vaccine to inmates and care workers.
According to available information, vaccines under development require two doses to be administered to each patient, which should be separated by a period of 21 to 28 days.
The government has also introduced new legislation that would allow more healthcare workers to give potential flu and covid-19 vaccines.
Who are the first categories on the list of coronavirus vaccine recipients?
The Joint Committee on vaccination and immunization examined data on those with the worst coronavirus fallout and those at the highest risk of death.
According to its interim guidance, the order of priority should be as follows:
Older adults in care homes and care home workers.
All adults 80 years of age or older and those working in the health and social care sector.
All adults 75 years of age or more.
All adults 70 years of age or older and people whose clinical status is considered very fragile, except for pregnant women and the age group under 18 years.
All adults 65 years of age or more.
Adults between the ages of 18 and 65 are classified as at risk.
All adults 60 years of age or older.
All adults 55 years of age or older.
All adults 50 years of age or older.
Where is the vaccine made?
Pfizer has a manufacturing site in Belgium while biontek has sites in Germany, and both will produce vaccine doses for Europe.
Health Secretary Matt Hancock told the BBC's Brexit programme: "we will have 800,000 doses next week, so this is the first start. Then we will distribute it at the pace of its production, and the responsible for the production of course is Pfizer in Belgium, so that's what will determine the speed of our distribution."
Doesn't it take a long time to produce vaccines?
Previously, vaccine production required years and sometimes decades.
Typically, vaccine production involves several design and development phases followed by clinical trials-which themselves need approval before they begin.
But for covid-19 vaccine trials, things look a little different. The process, which usually takes years, has been intensified and reduced to months.
While the initial design and development phases look similar, the clinical trial phases coincide rather than take place one by one.
Drug manufacturers also started the manufacturing process before getting final approval-and risked having to throw away everything they made.
The new way of working means that regulators around the world can start scrutinizing scientific data sooner than usual.
Yes, the data of the vaccine trials conducted by Oxford - AstraZeneca and Moderna indicate that they have two products with high efficacy.
According to Oxford data, the effectiveness of its vaccine is 62 percent when given a full dose followed by another full dose, but when people were injected with half a dose followed by a full dose at least a month later, the effectiveness of the vaccine increased to 90 percent.
The combined analysis of the two dosing methods showed an average efficacy of 70.4 percent.
The final results from the modernna vaccine trials show that it is 94.1 percent effective and 100 percent effective against severe cases of covid-19.
No one who was given the vaccine, known as mRNA-1273, developed a severe case of coronavirus.
Which vaccine is better?
All vaccine candidates initial log ratio of high potency but the researchers say, it is difficult to establish direct comparisons because it is not yet known what measures in the experiments.
How many doses did the UK secure?
The UK has secured the ability to use 100 million doses of the AstraZeneca - Oxford Vaccine, which is almost enough for the majority of the population.
It also recently entered into an agreement to obtain seven million doses of the Moderna vaccine in the United States.
The agreement covers four different categories: adenoviral-based vaccines, mRNA-based vaccines, inactivated whole virus vaccines and protein adjuvant vaccines.
The United Kingdom has secured the ability to use:
-100 million doses of Oxford Vaccine.
-60 million doses of Novavax vaccine.
- About 30 million doses of Jansen.
-40 million doses of Pfizer - biontik vaccine, the first agreement between the two companies with the government.
-60 million doses of a vaccine developed by valniva.
- 60 million doses of the adjuvant protein vaccine from GlaxoSmithKline and Sanofi Pasteur.
- 7 million doses of the "Moderna" vaccine in the United States.
What does it cost?
Pfizer - biontek launches its vaccine without profit.
According to reports, the Moderna vaccine may cost about 3 38 (£28) per dose while the Pfizer vaccine dose costs about دولارا 20 (£15).
Researchers suggest that producing the Oxford Vaccine may be relatively inexpensive, while some reports say it could cost £ 3 per dose.
Astra Zenica said it did not intend to profit from it, so that it would be available to all countries.
But the details of the agreements concluded by the British government is still under wraps.
How do we know that vaccines are safe?
The researchers report that their experiments did not indicate any significant risks related to safety.