“Follow-up tests confirmed that there was no HIV virus present, just a false positive on certain HIV tests,” CSL said in a statement on Friday.

“There is no possibility the vaccine causes infection.”

CSL said while phase one trials of the vaccine among 216 participants showed it was safe, it had decided not to progress with the trials following agreement with the federal government.

The company said blood samples from study participants were tested after vaccination and it was found antibodies caused a false positive for HIV.

Prime Minister Scott Morrison said the government has boosted orders for other potential vaccines to ensure there are still enough for the Australian population.

An extra 20 million doses of the AstraZeneca vaccine and a further 11 million of Novavax have been ordered.

Morrison reassured the public any vaccine would have to be given the tick of approval by the Therapeutic Goods Administration

“Without the tick there’s no jab,” he told reporters in Canberra.

“The truth is, we’re on track. The system’s working as it should and Australians are protected, as always.”

Department of Health boss and former chief medical officer Brendan Murphy said the rollout could even be quicker because more AstraZeneca vaccines had been ordered, as it’s already in production.

Professor Murphy said the potential candidate had looked promising as it was going to make antibodies for coronavirus.

But the confidence of Australians in a vaccine was more important.

“We can’t have any issues with confidence,” Professor Murphy said.

Queensland Premier Annastacia Palaszczuk said the outcome was disappointing.

“Of course, there is going to be some winners and losers,” she told Nine.

“It is very, very disappointing about the UQ vaccine but there are a lot of other candidates out there.”

The government is believed to have been told on Monday that UQ and CSL had abandoned the trials, with cabinet then agreeing to end the agreement to buy 50 million doses of the potential vaccine.

-with AAP