More than 425,000 people across the county have received their initial dose of the COVID-19 vaccine.
However, some sites are experiencing up to 60 no-shows per day.
Lincolnshire has two main vaccination centres, one at the Lincolnshire Showground and one at the Princess Royal Sports Arena in Boston, where staff can vaccinate 1,000 people a day.
A spokesperson for Lincolnshire’s Clinical Commissioning Group said the main reason people aren’t showing up is because of confusion in the booking system. They said: “People book via the National Booking System, then get the opportunity to book in (perhaps sooner) via their local GP practice, but don’t cancel their original appointment.
“We understand there are legitimate reasons why people might not be able to attend, but would encourage them to attend if possible, and if not, to cancel via the online booking system.”
University of Lincoln student, Caitlin Godfrey, volunteers as a marshal at the Robertson House vaccination centre in Stevenage.
Caitlin, 20, said: “It’s really frustrating that people aren’t coming to their appointments after booking, especially as the vaccines could be offered to others.
“While the side effects are unpleasant, they’re far better than having coronavirus and will protect you and others from it.”
For more information, visit the Government’s FAQs page.