The UK government confirmed its first doses of the new Pfizer-BioNTech COVID-19 vaccine have arrived in England.

The doses were transported in the back of trucks from the company's plant in Belgium to the UK via the Channel Tunnel, which runs between France and England.

The UK government is expected to start vaccinating care home residents and staff from Tuesday. National Health Service (NHS) workers  and people aged over 80 are next on the priority list.

The UK's business minister, Alok Sharma, said: "We are going to see some deployment this side of Christmas, but the bulk of it will take place in the new year."

The UK has ordered 40 million doses of the Pfizer vaccine. Each vaccine requires two doses administered three weeks apart. So that's enough for 20 million people, while the government says up to 800,000 doses should arrive this year.

When the vaccination program is rolled out nationally, mass-vaccination centers will be set up and the vaccine will also be available in doctors' surgeries and pharmacies. The military is helping with logistics and deployment.

The great challenge with the Pfizer vaccine is long-term storage, it has to be kept at minus 70 degrees Celsius. However, it can be stored for five days between 2 and 8 degrees Celsius.

Shane Brennan, CEO of the Cold Chain Federation, says the logistical challenges are immense.

"I think one area I would be worried about is making sure there are enough drivers in place in January through until June," Brennan explains. "We rely on European drivers to supplement our UK-based workforce. So there might be a crunch there."

Meanwhile, the top infectious diseases expert in the U.S., Anthony Fauci, has apologized for his comments about the speed at which the UK has approved the Pfizer vaccine.

On Thursday, he said: "The UK has decided to do it a little bit differently. They've gone over it very quickly and I can say, and this is not a criticism, they've done it in a way that is less deep than is being done by the FDA (Food and Drug Administration) in the United States."

Fauci now says he has a great deal of confidence in the UK's regulatory process.

The UK government will now be hoping the public agrees as it starts to roll out a vaccine produced in record time and one that could lead the country back to a normal life.