A hospital has accidentally administered the wrong second COVID-19 vaccine jab to a woman, in what is believed to be the first error of its kind in Britain, the Mail reported on Tuesday.

The patient — who wasn’t identified — turned up at the Great Western Hospital in Swindon expecting to receive another dose of the AstraZeneca vaccine.

But a mix-up meant she got the Pfizer vaccine instead, her husband told the Swindon Advertiser.

The woman said she felt okay afterwards but was left angry over the mistake. The hospital has launched an internal review into how the error happened.

Britain’s medical regulator says COVID-19 vaccines should not be mixed, and everyone should receive the same second shot as they did for their first one.

Scientists don’t believe it is unsafe to alternate shots but say more data is required to confirm this before the move is given the go-ahead. Oxford scientists are currently trialing whether the jabs can be alternated, in the hope of making them more potent.

The woman’s husband, who was also not identified, lashed out at the hospital and said they had made it clear his wife needed the AstraZeneca shot.

“I couldn’t believe it, it’s a huge error and very concerning,” he told the newspaper, saying “they told us this is the first time it’s happened — not just in Swindon but in the UK.”

The woman said that at no point during the appointment did the healthcare staff ask to see the card she got after her first jab, although it was face up on the table in clear view.

Great Western Hospitals said despite the mix-up, the woman will not now need a third jab because the second should work to boost immunity from the first.

“We have offered our sincere apologies for giving her a different COVID-19 vaccine as her second dose,” a spokesman for the Great Western Hospital said.