Hywel Dda University Health Board has extended its walk-in Covid-19 vaccination invite to those turning 18 before October 31.
The health board said it is in the process of identifying those residents to invite them to receive their Covid-19 vaccine at a mass vaccination centre.
However, to avoid any delay, the health board is encouraging all those nearly 18 years old living in Carmarthenshire, Ceredigion or Pembrokeshire to attend a walk-in clinic at one of its mass vaccination centres.
A health board statement said: "Please note the Pfizer-BioNTech vaccine is the only vaccine that can be given to those under 18 and is currently available at all Hywel Dda mass vaccination centres except Cardigan and the drive-through showground in Carmarthen.
"Cardigan’s mass vaccination centre will move from its current location to Yr Hen Ysgol Trewen, located at Cwm Cou (SA38 9PE) week beginning July 26 and the health board’s vaccination team is working on the ability to provide a supply of Pfizer for the south of Ceredigion county when the centre reopens in its new location.
"In the meantime, please come along and visit our other centres across the regions to get your vaccine."
The health board is urging anyone who is due a second dose of the vaccine to attend one of its mass vaccination centres.
A health board spokesperson said: "Second doses are essential for longer term protection, so it’s important that everyone comes forward for their full course when called.
"All second doses are now being given eight weeks following the first dose. If it has been more than eight weeks since your first vaccine dose and you haven’t received an appointment directly from us, get in touch."
As well as visiting a walk-in clinic at one of the mass vaccination centres, you can request an appointment online at hduhb.nhs.wales, call 0300 303 8322 or email COVIDenquiries.hdd@wales.nhs.uk
There is no need to contact the health board before attending a walk-in clinic.
Meanwhile, across Wales, 2,284,065 have received a first dose of Covid-19 vaccine and 1,946,526 are fully vaccinated.
In Hywel Dda, as of July 21, 516,019 residents have now received both jabs, with 9,392 given in the last seven days.
In Carmarthenshire (population 188,771) there have been 130,678 first jabs given and 109,721 second does, with 58.1% fully vaccinated.
In Pembrokeshire (population 125,818) there have been 90,932 first doses administered and 75,637 second doses, with 60.1% fully vaccinated.
And in Ceredigion (population 72,695) there have been 51,740 first jabs given and 43,029 second doses, with 59.2% fully vaccinated.
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