A 90-year-old UK grandmother has become the first person in the world to receive the Pfizer COVID-19 vaccine outside trials.

"I feel so privileged to be the first person vaccinated against COVID-19," Margaret Keenan told reporters after receiving the shot in the English city Coventry.

"It's the best early birthday present I could wish for, because it means I can finally look forward to spending time with my family and friends in the new year after being on my own for most of the year."

She added: "My advice to anyone offered the vaccine is to take it … If I can have it at 90 then you can have it, too."

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Margaret Keenan is just one of many people at the front of the line to receive the COVID-19 vaccine, including people over the age of 80, health care staff and care home workers. 

The second person to get the vaccine was a man named William Shakespeare.

Gill Rogers, 86, also received the vaccine on December 8. Her husband died from COVID-19 in April, and she has been grieving alone ever since because her immediate family was afraid of exposing her to the virus. 

These first recipients of the Pfizer vaccine will have to return to the hospital in 21 days to receive their second dose.

UK Health Minister Matt Hancock said he expects "several million" more doses to be distributed by the end of December.

However, the majority of people in the UK will not receive the vaccine until early 2021.

Prime Minister Boris Johnson called the vaccine roll-out a "huge step forward in the UK's fight against coronavirus." But he added: "[The UK] can't afford to relax."

The World Health Organization also said a vaccine on its own will not stop the pandemic.

The UK is not the only country to start vaccinating part of its population. Russia began vaccinating its high-risk workers on January 5. 

Video editor: Terry Wilson.