People in the South West are being encouraged to get a spring Covid-19 vaccination.
NHS England South West said more than half of people who were invited for the booster in the region had not taken up the offer.
People who are eligible for the Covid-19 vaccination include those who are aged 75 and over and people who are immunosuppressed.
The NHS said it had delivered nearly half a million vaccinations across the South West in the spring vaccination programme, which started on 1 April, including more than 24,000 to care home residents.
'Virus still circulating'
Dr Trevor Smith, regional medical director for NHS England South West, said: "There is still a large population who are eligible and have not yet come forward.
"The Covid-19 virus is still circulating and can be dangerous for those most at risk, such as older people or those who are immunosuppressed.
"Protection against Covid-19 can fade over time and there is now only one month left to get your spring Covid-19 vaccination, so it is important you come forward and book your appointment."
Appointments for the spring vaccination programme are available to book on the NHS website, though the app or by calling 119 until 16 June.
Walk-in clinics are also available, with the last appointments due to take place on 17 June.
