AstraZeneca Pauses COVID-19 Vaccine Trials Due to 'Unexplained Illness'

Damian McNamara

September 09, 2020

AstraZeneca today announced the temporary cessation of all their coronavirus vaccine trials to investigate an "unexplained illness" that arose in a participant.

The reported illness triggered a "standard review process" for the phase 3 trial of AZD1222, the company stated in a press release.

"As part of the ongoing randomized, controlled global trials, our standard review process was triggered and we voluntarily paused vaccination," an AstraZeneca spokesperson wrote in an email to Medscape Medical News when asked for more specifics on the unexplained illness.

"The event is being investigated by an independent committee," the spokesperson added, "and is it too early to conclude the specific diagnosis."

The New York Times, however, is reporting that the participant developed transverse myelitis, an inflammatory condition that affects the spinal cord, according to an anonymous source familiar with the situation.

Such a halt is "not uncommon at all," said Anthony Fauci, MD, head of the National Institute of Allergy and Infectious Diseases, in an interview on CBS This Morning. The illness may be unrelated to the vaccine and just happened to arise at the same time, he said, but "you can't presume that."

"This is an example of the kind of thing that you do to make sure when dealing with a product that it's safe," he said.

The company declined to provide a timeline for the safety review.

"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," AstraZeneca Chief Executive Officer Pascal Soriot said in the news release.

The news was first reported by Stat News yesterday.

Damian McNamara is a staff journalist based in Miami. He covers a wide range of medical specialties, including infectious diseases and neurology. Follow Damian on Twitter: @MedReporter.

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