Swansea Bay University Health Board have reassured that the coronavirus vaccine is safe after recent concerns over blood clots and the Oxford/AstraZeneca jab.
There are worries that vaccine hesitancy could be partly behind people missing their vaccination appointments.
Swansea Bay health board recently reported nearly 500 no-shows in just one day.
GP in the area, Dr. Christopher Johns, said people should be confident to attend their vaccine session because "the chances of having a very, very rare side effect are very, very small."
The Oxford/AstraZeneca jab is no longer being offered to people under the age of 30 in the UK after a possible link between it and rare blood clots.
There has only been one of these blood clot cases in Wales out of more than a million doses.
There have been 79 blood clot cases out of over 20 million doses that have been given.
Dr. Johns, a Swansea GP who works at a community vaccination hub in Sketty, said when people miss their appointments "it's a shame and it's an annoyance on the basis of the fact that it's quite straight forward to pick up the phone" to cancel.
In his own personal experience working in a community setting, he has not seen many no-shows but did acknowledge that they have been higher in the younger ages groups.
We have had some Do Not Attends (DNAs) which occurred a little bit more in the younger age groups of patients. In our over 80s population I would say we have virtually had 100% of people turning up on time at the correct time and very, very few DNAs so it restores a bit of faith.
One of the reasons believed to be behind some of the no-shows is vaccine hesitancy, something that has been of particular concern because of recent events concerning blood clots and the Oxford jab.
Dr. Johns said a "combination of factors" are behind why people do not show up but "vaccine hesitancy is playing a certain part".
He added: "It's those people we want to get to try and reassure them this is a safe vaccination and that the chances of having a very, very rare side effect are very, very small."
He predicts this will be "an ongoing situation" but health professionals need to continue to make sure patients "are aware of the risks of not being vaccinated as much as the risks of being vaccinated".
One woman who was more than happy to get her Covid vaccine was 91-year-old Dorothy. She believes getting a vaccine is "the most sensible thing for anyone to do".
When asked about concerns over blood clots from the Oxford/AstraZeneca jab, she said: "Well it's a very rare thing...it's a drop in the ocean.
"It's more than worth it, anyone who doesn't take it isn't very sensible I would say."
On April 8, UK regulator the MHRA issued new advice related to the Oxford/AstraZeneca vaccine after it was linked to a small amount of rare blood clots.
Those aged under 30 in the UK will now be offered other alternative Covid jabs and pregnant women should discuss having the Oxford vaccine with a health care professional.
Anyone who has already received their first dose of Oxford/AstraZeneca, should have their second one as planned.
The MHRA said there was a possible link between the jab and “extremely rare” blood clots but it has not yet concluded that the vaccine causes them. It emphasised that the benefits of the vaccine still outweigh the risks overall.
There has only been a total of 79 blood clot cases and 19 deaths reported, equalling a rate of around four cases per million.
Dr Shahid Akhtar explains why it is safe to get the vaccine during Ramadan
Healthcare workers are also urging Muslims not to let fasting during Ramadan stop them from getting the vaccine.
This week marked the start of the holy month when Muslims across the world fast between sunrise and sunset.
Dr Shahid Akhtar, from Aneurin Bevan University Health Board, said: "I can only reassure you that the vaccine is safe, is permissible, to take whilst you are fasting, and it is not something that will break your fast.
"This is according to a big consensus amongst Islamic scholars and also medical health professionals."