(Reuters) – Australia abruptly halted the production of a home-made vaccine against COVID-19 after trials showed it could interfere with HIV diagnosis, the developers said, with its makers instead agreeing to produce additional doses of a rival vaccine.
The inoculation being developed by the University of Queensland and vaccine maker CSL, one of four candidates contracted by the Australian government, was halted after “certain HIV diagnostic assays” returned false positives.
While there were no serious adverse effects seen in the Phase 1 trial of 216 participants, data showed antibodies that had developed interfered with HIV diagnosis and led to false positives on some HIV tests, CSL said.
Given the results, CSL said it had come to a decision with the Australian government to stop Phase 2 and Phase 3 trials of the vaccine.
“This outcome highlights the risk of failure associated with early vaccine development, and the rigorous assessment involved in making decisions as to what discoveries advance,” said Andrew Nash, CSL’s chief scientific officer.
The government had made a final decision “that the University of Queensland vaccine will not be able to proceed based on the scientific advice, and that will no longer feature as part of Australia’s vaccine plan,” Prime Minister Scott Morrison told reporters on Friday.
CSL will instead produce an extra 20 million doses of a vaccine developed by Britain’s AstraZeneca Plc, on top of the 30 million it is already producing, while the government has also secured more doses of Novavax vaccines, with whom it already has supply contracts.
Australia also has an agreement with Pfizer for 10 million dozes of its COVID-19 vaccine, with the country’s regulator expected to approve it by January 2021.
All up, Australia has secured 140 million vaccine units to inoculate its 25 million people, one of the highest ratios of vaccine purchases to population in the world, officials said.
Morrison said the government had not expected all four of the vaccine candidates it had chosen to come into production.
“If that had occurred that would have been truly extraordinary,” he said. “So that’s why we spread our risk.”
Australia is on track to start vaccinations in March and expects to have its whole population inoculated by the end of the year.
Its tally of 28,000 COVID-19 infections is far fewer than many other developed countries, and until Thursday Australia had gone nearly three weeks without any local transmission of COVID-19.