The 80-year-old Great British Bake Off judge was masked-up in the snap as a medic touched the injection site on her upper arm, appearing to hold a needle in the other hand.
"Who wouldn't want immunity from #Covid19 with a painless jab?? #vaccine," she captioned the photograph.
Watch: Piers Morgan vows to take the coronavirus vaccine LIVE on air!
Read more: Prue Leith shares stunning throwback photo
Her Bake Off co-star Noel Fielding commented: “Always the most classy glamorous person in the room x love you Prue x.”
While fellow judge Paul Hollywood added: “Well done Prue x.”
The vaccine is administered in two doses, at least 21 days apart. Currently those being prioritised include people aged 80 and over, those living and working in care homes and health care workers at high risk.
Margaret Keenan, 90, was the first person to get the Pfizer/BioNTech vaccine when it was rolled out last week.
Also among some of the first people to have it administered was 81-year-old William "Bill" Shakespeare.
Leith's post comes as comedian Jack Whitehall's 80-year-old father Michael, who frequently stars alongside his son, also shared a snap of himself in hospital getting the first part of the vaccine.
He joked: “Here was I worrying about a little prick, no, not @jackwhitehall, which was brilliantly organised by @GSTTnhs.
"Thank you to all the kind and wonderful NHS staff who administered my COVID-19 vaccine last night. See you for little prick No 2 in January.”
Watch: Man named William Shakespeare among first to get COVID vaccine