An Australian effort to develop a COVID-19 vaccine has been abandoned after trial volunteers returned false positive results for HIV.
The vaccine was being developed by Australian firm CSL and the University of Queensland, and fixing the error would have taken a year of research - prompting its backers to pull the plug.
The phase one trial volunteers didn't have the HIV virus, but developed antibodies which triggered positive results in HIV tests. There were no other adverse reactions reported, and the vaccine otherwise appeared to be working fine.
"I said at the start of vaccine development that there were no guarantees, but what is really encouraging is that the core technology approach we used has passed the major clinical test," said Prof Paul Young, the lead on the project.
"It is a safe and well-tolerated vaccine, producing the strong virus-neutralising effect that we were hoping to see."
But fixing the HIV problem would simply take too long, when speed is of the essence in fighting a pandemic that has killed 1.6 million people in less than 12 months.
"Doing so would set back development by another 12 or so months, and while this is a tough decision to take, the urgent need for a vaccine has to be everyone's priority," said Prof Young.
The problem is the vaccine's 'molecular clamp' technology, which uses part of an HIV protein.
"By itself, this is harmless and cannot cause an HIV infection or AIDS," wrote virus expert Adam Taylor of Griffith University for The Conversation.
"Rather, the vaccine's signature 'molecular clamp' technology was formulated with parts of an HIV protein. When injected, these prompted the production of antibodies that were picked up in a range of HIV tests.
"In other words, if the vaccine had been widely rolled out, this could lead many people to think they had HIV when they didn't."
Prof Young said the technology might still be useful in other vaccines - there's just not enough time to use it to fight COVID-19.
