Margaret Keenan, 90, is the first person in the world to receive a clinically authorized, fully tested coronavirus vaccine. She was given the shot at a hospital in Coventry, in central England, reported by the New York Times.

On Tuesday, the British National Health Service started distributing shots of the Pfizer-BioNTech Covid-19 vaccine, opening a public health initiative rendering Britons the first individuals in the world to obtain an approved, thoroughly tested vaccine.

“This is such an important product, it’s probably perhaps the most important product,” James Cleverly, Minister of International Affairs, said on Monday. “So we will look to ensure that those supplies are available in the U.K. in whatever circumstance.”

Six days after British authorities skipped ahead of the United States to become the first Western nation to approve a coronavirus vaccine, health professionals started delivering the vaccines, part of a national sprint to end a pandemic that has killed more than 1.5 million people worldwide.

Britain obtained 800,000 doses of the vaccine in the first shipment, the government added. In recent days, the vaccine has been shipped from a Belgian processing plant to government warehouses in Britain, and then to clinics, packaged in 975-dose trays at ultracold temperatures.

The shots will be provided by fifty clinics before the government will refine a proposal to include them in nursing homes and doctor's offices, too. The vaccine must be shipped at temperatures close to the South Pole, while Pfizer has confirmed that it can be processed before being used in a regular refrigerator for five days. Doctors and nurses, some persons aged 80, and care home staff would be the first to obtain the vaccine.

In recent days, several physicians and nurses have been invited to sign up for appointments, with the first shots being meant for people at the greatest risk of serious illness. The government also stated that the first to collect vaccinations would either be citizens over 80 who either have medical appointments planned for this week, or who are being released from those hospitals.

In the following weeks, nursing home patients who were expected to be the highest concern of the government would be vaccinated after health authorities began administering doses outside hospitals.

Given worries about the imminent division of Britain from the European Union to British warehouse shipment of the vaccine, the government said that it was willing, this week to allow the Army to fly doses across the borders.