Health bosses are concerned new cohorts entitled to the Covid vaccine are not taking up the offer because they don't think coronavirus will make them seriously ill.
Walk-in appointments are now being made available for 40 to 49-year-olds to ensure they get their first jab to protect them from the deadly virus.
Across Nottinghamshire, 860,553 vaccinations have now been administered with 65,821 given out in the last week across sites run by the Nottingham and Nottinghamshire NHS Clinical Commissioning Group.
In total, 320,789 second doses have now been administered.
This week, the vaccination programme continued to move through the age groups with people as young as 34 now able to get a jab.
Amanda Sullivan, from the Nottingham and Nottinghamshire CCG, said there were 31 people in local hospitals from May 18 with coronavirus.
Mark Spencer, MP for Sherwood, said he was aware some people fighting off the virus in hospitals had not taken up the jab opportunity.
Mrs Sullivan said: "We have got really good availability of appointments now for first and second doses. For first doses we have a lot of availability.
"Everyone over the age of 34 is eligible for a vaccine so please do book your slot.
"If you are between 40 and 49 you can simply walk into one of our main sites - we have a number of main sites where you can walk in.
"The link between having the vaccine and the chances of you needing to go to hospital and having serious illness with coronavirus is absolutely right.
"In terms of reasons why people are not coming forward - we are finding the older age groups have got really good coverage now but the younger age groups have not got the same level of coverage.
"The most recent cohorts that have come into the vaccine programme. There is still more to do there.
"People with health conditions might have concerns about the vaccine and if that is the case I would say please talk to health professionals or go along for your vaccine and talk to the health professionals there.
"Sometimes in younger age groups they feel they are less likely to get severe disease but unfortunately it can happen at any age.
"Being of younger age is not a reason not to have the vaccination. There are some geographical areas where we have targeted with pop up clinics.
"There is a number of things we are doing to try increase uptake where we are seeing some communities who are underserved at the moment."
