The trial of an Oxford coronavirus vaccine tipped to be the frontrunner in the fight against the pandemic could resume within days after it was halted.
AstraZeneca Plc - which is working alongside the University of Oxford - has confirmed it had had to pause development of the vaccine "to allow review of safety data".
It is believed a British volunteer suffered an adverse reaction during the trial.
Health industry website Stat, who first reported the vaccine pause, said the woman was on course to be discharged from hospital as early as last night.
It was described as a "temporary pause" by Pascal Soriot, the chief executive of Astrazeneca.
An AstraZeneca spokesperson described the pause as a "routine action" which must happen whenever a "potentially unexplained illness" occurs in one of its trials.
They said during the investigation it is crucial it "maintain[s] the integrity of the trials", adding the company is working to "expedite the review of the single event" in order to "minimise any potential impact" on the trial's timeline, according to The Times.
Speaking yesterday, Health Secretary Matt Hancock said that AstraZeneca's decision to pause its vaccine trial was a challenge but would not necessarily set back efforts to develop a vaccine.
"It is obviously a challenge to this particular vaccine trial," Hancock said on Sky News when asked about the pause in the trial. "It's not actually the first time this has happened to the Oxford vaccine."
Asked whether it would set back the vaccine development process, he said: "Not necessarily, it depends on what they find when they do the investigation."
The nature of the adverse reaction or when it occurred are not known but the participant is reportedly expected to recover.
AstraZeneca’s is the first Phase 3 Covid-19 vaccine trial of the nine front runners known to have been put on hold.
It only began its late stage trial in the US in late August, with 62 sites earmarked - while others were started in the UK, Brazil and South Africa.
