The UK just approved Pfizer's COVID-19 vaccine — here's who will be vaccinated first and how many people will get their shot in the coming weeks

• The UK on Wednesday approved the COVID-19 vaccine developed by Pfizer and BioNTech, making it the first Western country to authorize a coronavirus shot.
• About 800,000 doses will arrive in the country within a week, meaning 400,000 people could be vaccinated in the first wave, UK Health Secretary Matt Hancock told the BBC. The vaccine requires two doses, 21 days apart.
• Hancock said "many millions" of doses of Pfizer's vaccine could be available by the end of the year, but he refrained from giving an exact number.
• People in care homes and their carers are the highest priority for the vaccine, the government said, followed by anyone over 80 and frontline health workers.

The COVID-19 vaccine developed by the US pharmaceutical giant Pfizer and its German partner BioNTech was approved by the British drug regulator on Wednesday — making the UK the first Western country to give the green light to a coronavirus shot.

In a statement, the government said that the vaccine would be available within a week and that care-home residents and their carers would be first in line.

In total, the UK has ordered about 40 million doses of the two-shot vaccine, enough to immunize 20 million out of roughly 67 million people in the country. The two doses are given 21 days apart, and immunity kicks in seven days after the second dose.

How many people will be vaccinated first?

UK Health Secretary Matt Hancock told the BBC on Wednesday that the country would receive 800,000 doses of the vaccine next week from Belgium, where Pfizer is producing the UK's vaccine supply. This means 400,000 people will be vaccinated in the first wave of shots, he said.

"This will start small and ramp up," Hancock said. "The vast majority of vaccinations we expect to be in the new year."

Hancock said "many millions" of Pfizer's vaccine doses could be available this year, but he declined to state a precise figure.

"It depends on the speed of manufacture and how quickly we can get the batch testing done to the rigorous and high standards," he said. "Then once it's in the UK we need to obviously distribute it throughout the NHS throughout all four nations."

The vaccination process will take time, given that the vaccine requires two shots 21 days apart, Hancock added.

Who will be vaccinated first?

The UK government will prioritize the deployment of Pfizer's vaccine based on age and risk of severe coronavirus infection.

The two-shot vaccine will first be made available to care-home residents and those caring for them, people over the age of 80, and frontline healthcare workers, Hancock said.

"Then it essentially goes down the age range, also including the clinically extremely vulnerable," he added.

The Joint Committee on Vaccination and Immunisation, the clinical body that advises UK health departments, set out the details of this prioritization Wednesday.

The priority list starts with older people in care homes and workers there. Next are all people over 80 and those who work in healthcare and social care, followed by anyone over the age 75 and then over the age of 70.

The full priority list is here, starting with the highest priority:

• Residents in a care home for older adults and their carers.
• All those over 80 years of age and over. Frontline health and social care workers.
• All those 75 years of age and over.
• All those 70 years of age and over. Clinically vulnerable individuals.
• All those 65 years of age and over.
• All individuals aged 16 years to 64 years with underlying health conditions which put them at higher risk of serious disease and mortality.
• All those 60 years of age and over.
• All those 55 years of age and over.
• All those 50 years of age and over.

The government said the prioritization depended in part on vaccine supply.

"I'm confident now, with the news today, that from spring — from Easter onwards — things are going to be better. We're going to have a summer next year that everybody can enjoy," Hancock said.

Pfizer and BioNTech announced November 18 that their vaccine candidate was 95% effective at protecting people against COVID-19 in its late-stage trial.

The pharmaceutical giants plan to deliver 50 million doses across the world by the end of 2020, with production ramping up to produce more than 1 billion in 2021.

Additional reporting by Dr. Catherine Schuster-Bruce.