Nearly 20,000 Covid-19 vaccinations were administered across Suffolk and north east Essex in one day - the largest ever one-day total.
The achievement, which tallies up to more than the total population of Stowmarket, was achieved on December 19 with 19,836 doses administered.
This included boosters, first, second and third doses (for immunosuppressed people).
And those who are still to take up the offer of a jab are being reassured that it's not too late to get protected.
Dr Ed Garratt, chief executive of Suffolk and North East Essex Integrated Care System, said: "Sunday was an incredible day, with almost 20,000 vaccinations administered across the patch, which is more than the total population of Stowmarket or Walton-on-the-Naze.
"Those attending yesterday weren't just there to receive a booster. It was really pleasing to see a number of people mindful of the sweeping spread of the Omicron variant and the very real risk it presents to individuals, their families and the wider community.
"There are many reasons why some people have not yet come forward. I want them to know it's not too late.
"In fact, it's more important than ever to come forward. Please don't risk your own health and that of others.
"We're here for you and hope to see you soon."
Almost 100 walk-in vaccine clinics are being held across Suffolk and north east Essex, or appointments can be booked ahead of time.
Questions or concerns causing vaccine hesitation can be raised with a trusted health professional via the local helpline on 0344 257 3961. The helpline staff will not judge and will offer reliable information.
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