A reserve list covering vaccination “no-shows” has helped the country’s largest health board keep wasted doses to around just 300 in total since immunisation began.

The figures for Betsi Cadwaladr University Health Board come after various claims on social media that people were refusing to honour vaccine appointments, doses were being wasted wholesale, and even one claim by a Senedd Member that 700 were thrown away because they were out of date.

The latest figures from Public Health Wales show 62,363 vaccinations have been carried out by Betsi Cadwaladr up to 24 January, although the real figure will be far higher due to a lag in inputting statistics.

In all, around 0.5 per cent of vaccines (311) have been wasted, despite the unstable nature of the Pfizer/BioNtech version which has to be stored between -70C and -80C and problems over storage once unfrozen.

This includes wastage as a result of technical issues when preparing doses.

The jab must be thawed over a period of three hours, mixed with sodium chloride and then stored in refrigerators before being used within six hours if readied for dosing – and only two if it hasn’t been diluted.

Betsi Cadwaladr’s Charlotte Makanga is a consultant antimicrobial pharmacist, closely involved in the rollout of Covid-19 vaccines at the board’s three mass vaccination centres in Bangor, Llandudno and Deeside.

She said: “One box of the Pfizer vaccine contains 195 vials and each vial contains 6 doses, so a tray about the same size as a small dinner plate provides 1,170 doses.

“We are typically seeing around 3 per cent of people who aren’t able to attend an appointment at our mass vaccination centres.

“There are a number of reasons for this, including people who are self-isolating, or people who are unable to have the vaccine because they have tested positive for Covid-19 in the last 28 days.”

That means around 1,900 out of more than 62,000 people have failed to take up their vaccine slots, but the reserve list is taking up the vast majority of those missed appointments, said Ms Makanga.

She explained: “Because we operate a reserve list for people in priority groups, we have experienced very minimal vaccine wastage as a result of missed appointments.

“This is testament to the dedication of staff in mass vaccination centres who regularly go above and beyond, working late into the evening.”

There have been many unsubstantiated rumours about wastage of the vaccine on social media, including one high-profile one in a since-deleted tweet from Conservative Senedd Member for Aberconwy Janet Finch-Saunders.

She claimed 700 out of date vaccine doses had to be thrown away at Venue Cymru Rainbow Hospital – a charge quickly refuted by Betsi Cadwaladr.

Wastage should become even less of an issue as more of the British Oxford/Astra Zeneca vaccine filters into the system, as it is more stable and easier to store than its German/American counterpart.

Ms Makanga added: “We all know just how precious the vaccine is and one dose wasted is one less person receiving it.”