UK-based biopharma giant AstraZeneca has said that the phase 3 testing of its COVID-19 vaccine being developed in tandem with Oxford University has been put on hold, due to a suspected serious adverse reaction in a participant in the United Kingdom.
The pharma company described it as a "routine" pause in the case of "an unexplained illness". The outcome of vaccine trials is being closely watched around the world. The AstraZeneca-Oxford University vaccine is seen as a strong contender among dozens being developed globally.
The nature of the adverse reaction and when the development took place were not initially clear, although the participant is expected to recover, said an individual familiar with the matter. He added that the trial was paused out of "an abundance of caution." A second individual, who is also aware of the development said the finding has impacted other AstraZeneca vaccine trials that are underway and other clinical trials being conducted by several vaccine manufacturers.
It is not known when the clinical trial of the AstraZeneca's vaccine will resume.
It is to be noted that AstraZeneca is the first Phase 3 COVID-19 vaccine trial known to have been paused. The trial in the US is currently underway at 62 sites across the country, although some have not started enrolling participants.
Phase 2 and 3 trials previously began in the UK, South Africa and Brazil.
According to a Phase 1/2 study published in July, around 60 per cent of the 1,000 participants experienced side effects after being administered the vaccine. All the side effects like fever, headaches, muscular pain and injection site reactions were deemed mild or moderate.
According to the AstraZeneca statement, "in large trials, illnesses will happen by chance but must be independently reviewed." The spokesperson also said the company is "committed to the safety of our participants and the highest standards of conduct in our trials."
The Indian pharmaceutical giant, Serum Institute of India, however, clarified that testing of the possible vaccine candidate in India is ongoing and has not faced any issue so far.