The company said that the pause was "to allow review of safety data by independent committees and global regulators".
This last Tuesday morning, AstraZeneca was among 9 pharmaceutical companies to sign a letter pledging the continued assurance and monitoring for safety and tolerability in the first COVID-19 vaccine candidates, in response to reports that a vaccine may be regulated and distributed in alignment with the upcoming US Presidential Election in November. AstraZeneca officials this week said it's possible the vaccine could be ready for approval by the year's end if trials resumed quickly.
The illness that triggered the worldwide pause, which occurred in a woman who was in the vaccine arm of the United Kingdom trial, has not been officially disclosed, though AstraZeneca CEO Pascal Soriot told a group of investors on Wednesday that her symptoms were consistent with transverse myelitis, a serious condition involving inflammation of the spinal cord that can cause muscle weakness, paralysis, pain and bladder problems.
Pauses in drug trials are commonplace.
The DSMB has, however, recommended that the study be paused until the investigations in the serious adverse event. "All trial investigators and participants will be updated with the relevant information and this will be disclosed on global clinical registries, according to the clinical trial and regulatory standards", it added.
Scientists and others around the world, including experts at the World Health Organization, have sought to keep a lid on expectations of an imminent breakthrough for coronavirus vaccines, stressing that vaccine trials are rarely straightforward.
The vaccine being developed by Oxford and AstraZeneca is widely perceived to be one of the strongest contenders among the dozens of coronavirus vaccines in various stages of testing around the world.
Late last month, AstraZeneca began recruiting 30,000 people in the US for its largest study of the vaccine.
A general view shows laboratory technicians take part in filling and packaging tests for the large-scale production and supply of the University of Oxfords COVID-19 vaccine candidate, AZD1222, conducted on a high-performance aseptic vial filling line on September 11, 2020 at the Italian biologics manufacturing facility of multinational corporation Catalent in Anagni, southeast of Rome, during the COVID-19 infection, caused by the novel coronavirus. This is the second known hold of studies of the AstraZeneca vaccine.
Johnson & Johnson plans to start this month a late-stage study of its vaccine in up to 60,000 people in several countries including the U.S.