As part of the ongoing clinical trials of the AstraZeneca Oxford coronavirus vaccine, AZD1222, a standard review process has been triggered, resulting in the voluntary pause of vaccination across all trials to allow an independent committee to review the safety data of a single event of an unexplained illness that occurred in the UK Phase III trial.

This routine action happens whenever there is a potentially unexplained illness in one of the trials. In large clinical trials, illnesses must be independently reviewed. AstraZeneca is working to expedite the review of the single event to minimize any potential impact on the trial timeline.

Pascal Soriot, Chief Executive Officer, said: “At AstraZeneca we put science, safety and the interests of society at the heart of our work. This temporary pause is living proof that we follow those principles while a single event at one of our trial sites is assessed by a committee of independent experts. We will be guided by this committee as to when the trials could restart, so that we can continue our work at the earliest opportunity to provide this vaccine broadly, equitably and at no profit during this pandemic.”

AZD1222 was co-invented by the University of Oxford and its spin-out company, Vaccitech. It uses a replication-deficient chimpanzee viral vector based on a weakened version of a common cold virus (adenovirus) that causes infections in chimpanzees and contains the genetic material of the SARS-CoV-2 virus spike protein. After vaccination, the surface spike protein is produced, priming the immune system to attack the SARS-CoV-2 virus if it infects the body.