Australia rules out Covid-19 vaccine that produced false positives for HIV

Australia on Friday canceled an approximately $ 750 million plan for a large order for a locally developed coronavirus vaccine after the inoculation produced false positive results for HIV in some volunteers participating in a trial study.

Of the dozens of coronavirus vaccines being tested around the world, the Australian was the first to be abandoned. While its developers said the experimental vaccine appeared to be safe and effective, false positives ran the risk of undermining confidence in the effort to vaccinate the public.

Prime Minister Scott Morrison said on Friday that his government would make up for the loss of 51 million doses it had planned to buy from the Australian consortium in part by increasing orders for vaccines made by AstraZeneca and Novavax. The government has said it plans to start vaccinating citizens in March.

“We can’t have any problem with confidence,” he told reporters, “and as a nation now, with a good portfolio of vaccines, we can make these decisions to better protect the Australian people.”

The Australian setback showed the missteps that can inevitably occur when scientists, during a pandemic that has killed more than 1.5 million people, rush to condense the usual years-long process of developing vaccines into a matter of months.

But just as Australian scientists made their announcement, the fruits of that race became clearer. The United States took another step toward issuing its first approval for a Covid-19 vaccine, as a panel of experts advising the Food and Drug Administration approved a Pfizer vaccine that is already in use in Britain.

The problem that arose with the Australian vaccine, developed by the University of Queensland and the biotechnology company CSL, was related to the use of two fragments of a protein found in HIV.

The protein was part of a molecular “clamp” that the researchers attached to the spikes that surround the coronavirus and allow it to enter healthy cells. The clamp stabilizes the spikes, allowing the immune system to respond more effectively to the vaccine.

Using the HIV protein posed no risk of infecting the volunteers with that virus, the researchers said. But the clamp led to the production of antibodies recognized by HIV tests at higher levels than scientists expected.

Because the HIV tests could not be quickly redesigned to account for this, the researchers decided to abandon vaccine development. Proceeding could have sparked widespread anxiety among Australians that the vaccine could cause AIDS.

The first experiments with hamsters showed that the vaccine protected them from the coronavirus. When Phase 1 human trials began in July, the 216 volunteers were “fully informed of the possibility of a partial immune response” to the clamp, the University of Queensland and CSL said in a statement Friday.

The mistake, said John P. Moore, an immunologist at Weill Cornell Medical College in New York, was an “honest mistake” that cost money, not human lives.

“I’m sure a lot of people are very embarrassed,” said Professor Moore. “It’s not cool to be associated with a bug like this. But when you’re running 90 miles per hour, sometimes you stumble. “

The University of Queensland vaccine was one of several in development that contains a coronavirus protein that elicits an immune system response. Protein-based vaccines have a longer history than some of the newer approaches used by competing coronavirus vaccines, such as those based on viral genes or so-called adenoviruses.

The major protein-based vaccines include one made by Maryland-based Novavax, which is in Phase 3 trials, and another from Clover Biopharmaceuticals of China, which is in Phase 1 trials.

In the case of the Australian vaccine, it was found to produce a strong immune response and did not cause serious side effects in the phase 1 trial, according to the scientists’ statement. But continuing to test the vaccine would have required “significant changes” in long-standing HIV testing procedures, they said.

“Doing so would delay development for another 12 months or more, and while this is a difficult decision to make, the urgent need for a vaccine should be everyone’s priority,” Paul Young, a virologist at the university who helped lead the effort vaccine said in the statement. He did not immediately respond to a request for comment Friday afternoon.

Australian Health Minister Greg Hunt told reporters that the country still had access to 140 million units of coronavirus vaccines, more than enough to cover its population of around 25 million people.

“This is the scientific process that works,” Hunt said. “It’s the planning process working. It’s an honest explanation of some of the challenges we’ve had. “

Carl Zimmer contributed reporting.