A highly anticipated vaccine for COVID-19 developed by UK drugmaker AstraZeneca has been put on hold, for a safety review, after a participant showed a "suspected serious adverse reaction" during trials.
That's according to the health news website Stat News on Tuesday (September 8), which quoted an AstraZeneca spokesperson.
The nature of what it called an "unexplained illness" and when it occurred has not been disclosed.
However the report said the the participant is expected to recover.
AstraZeneca is developing the vaccine alongside the University of Oxford and late-stage trials are underway in sites including the U.S and the U.K., which is where the participant apparently fell ill.
The spokesperson said the trials were being paused to "allow review of safety data."
AstraZeneca has been seen as a frontrunner in the vaccine race and in May the U.S secured almost a third of the first 1 billion doses.
And just this week, Australia announced they had placed an order for 3.8 million doses of the potential vaccine, if trials were successful.
On Wednesday the country's deputy Chief Medical Officer told Sky News he wasn't worried about pausing trials and that it's a positive thing because quote "safety is the priority of the clinical trialists and investigators."
AstraZeneca's decision to put the trial on hold came after it made a pledge alongside eight leading vaccine developers Tuesday.
It was joined by Pfizer and GlaxoSmithKline in vowing to uphold scientific standards for their immunisations in the global race to contain the pandemic even in the face of political pressure to rush out a vaccine.