It has reached that figure in just four months since opening at the Princess Royal Sports Area in the town.
And those in charge say they are incredibly proud of the effort everyone involved has put in to make the vaccination programme such a success.
It was just seven weeks ago that the centre celebrated reaching 50,000 vaccinations.
Lynda Stockwell, Clinical and Operational Lead at the PRSA, said: “From the beginning when we were vaccinating people over the age of 80, to now when we’re focusing on first vaccinations for people 30 and over, as well as second doses, it has been a challenge.
“The superb team of clinical and non-clinical staff we have assembled at PRSA have made it happen and made it fun at the same time.”
PRSA is one of two Mass Vaccination Centres in Lincolnshire, along with the Showground Mass Vaccination Centre near Lincoln. The county also has a network of 13 Local Vaccination Centres run by local GP practices.
“It is difficult to describe how I feel about what we have achieved since mid-January, but it would be fair to say that I am hugely proud of the team at PRSA and what we have achieved.
“An awful lot of people have put a huge amount of effort into making this happen and getting PRSA operational as a Mass Vaccination Centre, and the 100,000 vaccinations is down to them.”
Martin Fahy, Director of Nursing and Quality, NHS Lincolnshire CCG, said: “We know it has been non-stop for Lynda and her team since the beginning and we are enormously grateful for everything they have done, not to mention hugely proud of them.
“The work undertaken by the team at PRSA, and also at the other vaccination sites across the county, is nothing short of inspirational.
“The ongoing vaccination programme represents the best way of combatting covid, so we continue to strongly urge anyone eligible to come forwards for their vaccination when called.”
Linda said: “The majority of people who have come to PRSA for their vaccination have been very grateful to have had the opportunity to do so.
“Most days we are vaccinating in excess of 1,000 people a day, so there are times when we have to ask people to be that little bit more patient with us, but I think that, for most people, getting vaccinated makes it all worthwhile.”