One of Australia's vaccine frontrunners AstraZeneca has put trials on hold over a 'concerning' adverse reaction

• AstraZeneca has halted trials on its vaccine candidate on Wednesday after one participant experienced an adverse reaction.
• With details scant, a spokesperson told Business Insider Australia an independent review would now be conducted and expedited to determine what had happened.
• A bioethicist meanwhile said that, while it was “cause for concern”, it was to be expected in a trial as large as this.
• Visit Business Insider Australia’s homepage for more stories.

The global pharmaceutical company behind one of Australia’s biggest coronavirus vaccination hopes has suspended trials after a participant experienced an adverse reaction.

AstraZeneca revealed on Wednesday that it had momentarily stopped work its vaccine being developed with Oxford University.

“As part of the ongoing randomised, controlled global trials of the Oxford coronavirus vaccine, our standard review process was triggered and we voluntarily paused vaccination to allow review of safety data by an independent committee,” a company spokesperson told Business Insider Australia.

“This is a routine action which has to happen whenever there is a potentially unexplained illness in one of the trials, while it is investigated, ensuring we maintain the integrity of the trials.”

The specifics of what happened during the UK trial are expected to emerge in the coming days.

The company now said the incident would now be subject to an “independent review”, expedited to minimise disruption to the vaccine’s timeline. This week, it said that the vaccine could be ready for production in Australia in early 2021.

Under existing agreements and pending regulatory approvals, 30 million doses of a successful vaccine would be manufactured locally by Australian biotech company CSL.

While concerning, the event is to be expected as part of trials on this scale, according to bioethicist Xavier Symons.

“We’re talking about approximately 50,000 participants across several countries, including the UK, South Africa, Brazil and the US so it’s a very big trial that is in the midst of a very big stage of that process,” Symons, a research fellow at the Australian Catholic University (ACU), told Business Insider Australia.

“This development we’ve heard about this morning is to some extent not unexpected as far as clinical trials go, but it is cause for concern and it’s important people understand what it means.”

The review will now attempt to identify what happened and if the vaccine caused the illness.

“That’s the big question. But it’s obviously serious enough for AstraZeneca to decide to halt the trial process,” Symons said.

“Because we need a vaccine, this whole process will be expedited. It’s not as if they’re going to cut corners but they’ll at least try to cut red tape so they can conduct a review as quickly as possible.”

That means that the review will “unmask” the trial to understand who was receiving the vaccine and who was part of the control group.

If the participant was receiving the placebo, then the trial will soon be able to continue as normal, Symons said. If not, the trial may need to be changed before it proceeds. That could mean that eligibility criteria for the vaccine could be adjusted with some pre-existing conditions potentially excluded.

However, that result may not be known for some days yet, with researchers and Australians having to wait and see.