The EU's drug regulator will decide on Monday whether to authorise the Pfizer-BioNTech coronavirus vaccine, with desperate countries hoping for the green light to finally start inoculating their citizens.
The Amsterdam-based European Medicines Agency dramatically moved the decision on the jab ahead from December 29, following pressure to accelerate the process from Germany and other EU states.
The clamour for action grew as Britain and the United States have already started giving their citizens the vaccine developed by US giant Pfizer and German firm BioNTech under emergency national rules.
The EU will start COVID-19 inoculations on December 27 providing the EMA grants a one-year conditional marketing authorisation, the European Commission has said.
The regulator said it had worked around the clock to speed things up, but needed to make sure the Pfizer-BioNTech vaccine was safe and effective, in order to avoid any doubts that could affect uptake.
"We have been able to revise the timetables for the evaluation of the COVID-19 vaccines due to the incredible efforts of everybody involved in these assessments," EMA chief Emer Cooke said last week.
"The number of infections is increasing across Europe and we are aware of the huge responsibility we have to get a vaccine to the market as quickly as is feasible, whilst maintaining the robustness of our scientific review."
The EMA said that if a decision is not possible at the meeting on Monday, then it will hold another meeting on the original December 29 date to rethink.
A decision on another vaccine produced by US firm Moderna is due by January 6.
German pressure
The Pfizer-BioNTech vaccine has proven to be 95 per cent effective in global trials where two doses are injected three weeks apart.
It must be stored at -70 degrees Celsius (-94 degrees Fahrenheit), a temperature much lower than standard freezers and which forced the company to develop special containers for transport.
The EMA has been carrying out a so-called "rolling review" on the vaccine involving lab tests and large-scale human trials over the past few months, speeding up a process that normally lasts years.
The regulator can grant medicines a conditional marketing authorisation for the EU in public health emergencies. It then follows up with further tests to make sure there are no problems down the line.
The EMA had originally said it would decide at a meeting of medicines experts to be held at the latest on December 29.
But Britain -- the pre-Brexit home of the EMA until last year -- the United States and Canada meanwhile pushed through emergency authorisation which meant they could start vaccinating sooner.
EU leaders complained at an EU summit earlier in December, and Germany then weighed in last week.
Hours later, the EMA announced it had received new data from Pfizer-BioNTech and would make its decision on December 21 instead.
Meanwhile, the EMA has also had to contend with a cyberattack in which data from the Pfizer-BioNTech and Moderna vaccines was stolen.
If the EMA gives the green light on Monday, the European Commission will then rubber-stamp it within days so vaccinations can start on December 27 across the bloc of 450 million people.
What is the EMA?
The EMA is the regulator for all human and animal medicines in the 27 nations of the European Union. It tests drugs and vaccines for safety and efficacy. Britain is also bound by its rules until the end of the post-Brexit transition period on January 1.
The EMA moved from London to Amsterdam in 2019 after Britain left the EU.
What is it deciding on Monday?
The EMA's Committee for Medicinal Products for Human Use will decide whether to recommend approval for a year-long Conditional Marketing Authorisation (CMA) for Pfizer-BioNTech's coronavirus vaccine within the EU.
The regulator is allowed to grant a CMA for a medicine during public health emergencies when it can show that the benefits of using it outweigh the risks of speeding up a process that normally takes years.
The EMA has been carrying out a so-called "rolling review" of data from lab tests and clinical trials for the vaccine as they come in. Normally it would only review the data after it has all been collected.
A decision on the vaccine by US firm Moderna will be made at a meeting on January 6.
Too slow?
Britain, the United States, Canada, Switzerland, Singapore and Bahrain have all given the green light for the Pfizer-BioNTech jab, meaning that vaccination could get underway.
The EMA was originally going to decide on the vaccine on December 29 but it brought the date ahead by eight days after Germany and other European states complained about the delay.
If the EMA committee fails to reach a decision on Monday it will hold another meeting on December 29.
What does the EMA say?
The EMA says Britain and the US have only given temporary emergency use authorisation for the vaccine, which requires fewer tests and has to be renewed more frequently.
By contrast, it says the Conditional Marketing Authorisation requires a more rigorous testing procedure, and that it lasts a year, with follow-up tests afterwards.
It is also "paramount" to ensure public trust in the vaccine at a time when scepticism and disinformation are rife, an EMA source told AFP.
Did Brexit make UK quicker?
British ministers said it did. But it later emerged that Britain was still under the EU's rules during the Brexit transition, however it was allowed to opt-out in emergencies.
All EU states were allowed to do so, but made a political decision to go for CMA together to show unity, and to start vaccinations at the same time.
Arguably Brexit had an effect because the EMA took time to work back up to full capacity after its move from London, according to a mid-year report in October.
But there were other factors too, with new EMA chief Emer Cooke only starting the job in November.
The agency also had to deal with a major cyberattack in which documents relating to the Pfizer-BioNTech and Moderna vaccines were stolen, although it insisted the hack didn't affect the vaccine timeline.