CANBERRA, Australia (PNN) - December 11, 2020 - The Australian government has canceled further development of a COVID-19 vaccine after several trial participants had false positive tests for HIV. The vaccine was being developed by the University of Queensland, while Australian biotech company CSL Limited had been under contract to provide 51 million doses. The vaccine had been on schedule for mid-2021, with phase two and three clinical trials due to commence in December.
On Friday, however, Australian Prime Minister Scott Morrison announced that the “University of Queensland vaccine will not be able to proceed based on scientific advice, and that it will no longer feature as part of Australia’s vaccine plan,” adding, “I think the decision we’ve made today should give Australians great assurance that we are proceeding carefully, we are moving swiftly, but not with any undue haste here.”
“Our processes will not be compromised. At the end of the day, the Therapeutic Goods Administration - like with any vaccine in Australia - must give their tick-off. Without the tick, there’s no jab when it comes to vaccines in this country. That is true for the COVID-19 vaccine, as it is true for any other vaccine that is administered here in Australia,” Morrison added.
The vaccine was one of four secured by the Australian government, which will now turn its focus to the AstraZeneca vaccine as well as Pfizer’s.
CSL said in a Friday statement that “following consultation with the Australian government, CSL will not progress the vaccine candidate to phase 2/3 clinical trials.”
The decision to drop the University of Queensland vaccine was over fears that the false positive results would scare Australians away from the vaccine, despite the fact that patients had not actually contracted the disease.
The now-canceled vaccine focused on the COVID-19 “spike protein” using “molecular clamp technology” to lock the protein into a shape that the human immune system can identify and neutralize. To ensure an immune response, the clamp chosen to trick the immune system into attacking includes two fragments of a protein found in HIV, which by themselves do not pose a threat.
Trial participants were advised of the possibility that vaccine-induced HIV antibodies might be detected as a result, but it was nonetheless unexpected. Subsequent HIV tests provided definitive negative results in the trial participants.
While the HIV tests were false positives and there was no risk to the trial participants, significant changes would need to be made to well-established HIV testing procedures to accommodate rollout of this vaccine, the researchers said. The Phase 1 trial will continue, where further analysis of the data will show how long the antibodies persist.
Professor Paul Young, co-lead researcher on the vaccine, said that it would be possible to re-engineer it to avoid false positives but there wasn’t enough time. “Doing so would set back development by another 12 months or so, and while this is a tough decision to take, the urgent need for a vaccine has to be everyone’s priority,” he said.
Health Minister Greg Hunt said that while the HIV test results were false, “the scientific advice is that the risk to vaccine confidence was the principal issue here.”
Meanwhile, Australia has secured contracts for 140 million doses of vaccine, “one of the highest ratios of vaccine purchases and availability to population in the world” according to Hunt, who added, “What we can do is vaccinate our population twice over.”