Residents of Kent will today be among the first in the world to receive the coronavirus vaccine as it is rolled out at one of the county's hospitals.

The William Harvey Hospital in Ashford is one of 50 hubs to be administering the initial wave of the Pfizer/BioNTech Covid-19 vaccine.

Watch: Ashford GP Dr Jack Jacobs talks about the vaccine

NHS staff have been working throughout the weekend to prepare for today's launch, ready to welcome the first recipients of the vaccination through the hospital doors this morning. It follows the government's emergency authorisation to distribute the vaccine last week.

The UK ordered 40 million doses after the vaccine was shown to be 95% effective having been tested on 43,000 people, with no safety concerns.

And 90-year-old Margaret Keenan hailed the vaccine the "best early birthday present" she could have wished for and urged others to follow her lead as she became the first person in the world to be vaccinated this morning.

A complicated journey

The Pfizer/BioNTech vaccine arrived at the William Harvey Hospital yesterday, in preparation to administer the dose to the most vulnerable people in the county.

But this only marks the tail end of its long and complex journey to the Kent hospital.

The Covid-19 vaccine is being manufactured in a small town of Puurs in northern Belgium, once upon a time primarily known for its famous 8.5% Duvel beer.

The Pfizer plant has been pumping out hundreds of thousands of jabs ready for today's first wave rollout, which have been transported to the UK over the past week.

But unlike other coronavirus vaccines, such as the Oxford vaccine, the Pfizer/BioNTech jab is extremely temperature-sensitive.

It has to be stored in temperatures between -70C and -80C before being thawed out and can be moved only four times within that cold chain before being used.

To put that in perspective, a -72C environment would cause your car tyres to shatter.

This has resulted in complex logistical planning by Pfizer and BioNTech to make sure none of the jabs are spoiled during their cross-continental journey.

Once the vaccine arrives in the UK, it has to go through a rigorous post-delivery check to ensure the integrity of the jab has been maintained.

This process alone can take up to 24 hours, with temperatures having to be manually checked against shipment temperature data supplied by Pfizer.

Each box of vaccinations is opened and unpacked, with the specialist medical teams keeping tabs on the temperature at all times.

If the quality assurance teams are happy with the state of the dispatched vaccines, they are then sent to authorised sites across the UK to be administered.

But even delivering the vaccine to the William Harvey and other hospitals around the UK has been challenging due to the need of storing it in icy temperatures.

Public Health Englnd (PHE) on Saturday released images of the freezers used to store the vaccine before they are sent to each hospital hub.

The storage units, which are not portable, each hold around 86,000 doses and are stored in a secure location somewhere in the UK.

They are then transferred to a special container the size of a suitcase, capable of holding around 5,000 doses.

These containers have to be replenished with dry ice every five days to keep the doses at the required temperature.

The Department of Health and Social Care (DHSC) explained that the careful process of defrosting the doses takes a couple of hours, with more time being required to prepare the vaccine ready to be administered to the first recipients.

Once the vaccine has been properly thawed out, it can be stored in a standard fridge for up to five days at hospitals such as the William Harvey.

Who will get the vaccine?

Care home residents and carers, patients aged 80 and above who are already attending hospital as an outpatient, and those who are being discharged home after a hospital stay will be among the first to receive the Pfizer/BioNTech jab from today.

The William Harvey will also begin inviting over 80s in for a jab and work with care home providers to book their staff in to vaccination clinics.

Any appointments not used for these groups will be used for healthcare workers who are at highest risk of serious illness from Covid-19.

When further supplies of the vaccine become available, vaccination centres will also open in sporting venues and conference centres, with the capacity to treat large numbers of patients.

NHS England has drawn up a priority list to reveal who can expect to be invited to have the vaccine administered.

Children and people aged 16 to 49 without underlying health conditions are not being treated as a priority, due to the threat of the virus to elderly people and those with pre-existing medical issues.

Pregnant women will not be part of the vaccine programme for the time being, as no pregnant women were included in the trials conducted.

Children under 12 are also excluded as they were not included in the trial, and there is not enough data available on children between 12 to 15 to allow that age group to receive the dose.

Although today is the beginning of the rollout, it will take a little longer for vaccinations to be administered en masse.

A small number of GP-led primary care services across the UK will begin delivering the jab from next week, with more practices expected to begin throughout December and into 2021.

Eventually NHS England expects large-scale vaccination centres to be able to deliver the vaccine to more people, as a larger supply of doses becomes available.

It has also been reported that the Queen will receive the vaccine "within weeks".

What happens after getting the vaccine?

Those receiving the Pfizer/BioNTech vaccine at the Ashford hospital today will be asked to return in three weeks for a second dose.

The reason two doses are needed is because the second shot is required for the body to attain immunity to the virus.

During its trial process, only mild side effects were reported from people who were administered doses.

These included fatigue and headaches after the second dose, but this was only 4% and 2% respectively.

Another side effect was muscle pain in the place participants had received the injection, but as Özlem Türeci, chief medical officer at BioNTech explained, that is a common reaction with a vaccination of other types too. Speaking last week, deputy chief medical officer for England Professor Jonathan Van-Tam said: "To all those who are eligible – this is the start of vaccine supply for the UK.

"In time, you will be invited to book your appointments to get your vaccinations. I urge you to be ready, and to help make the process as smooth as possible. For now, stay patient, and keep yourselves safe by continuing to follow the rules and maintaining social distancing."

Will people receiving the vaccine still be able to transmit Covid?

The trial conducted by the pharmaceutical giant was not designed to test whether the vaccine can prevent transmission of coronavirus, so it is not clear yet.

"I'm obviously delighted that the vaccine hasn't just arrived - but arrived in Ashford."

Speaking to the American network NBC last week, Pfizer CEO Albert Bourla said: "I think this is something that needs to be examined. We are not certain about that right now with what we know."

Studies are ongoing though, so we may get an answer to that question as the vaccine is rolled out in the coming months.

Ashford MP Damian Green is encouraging people to get the vaccine regardless, saying it is essential in the fight to stop Covid-19.

He said: "I'm obviously delighted that the vaccine hasn't just arrived - but arrived in Ashford.

"It'll cheer people up in what are bleak times and we can now see a way out.

"It's great news both for the health workers and care home residents.

"Please take it - it's essential that there's as high a take-up as possible. I'll be getting vaccinated as soon as my turn in the queue comes."

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