More on Pharmacy

AstraZeneca puts COVID-19 vaccine trial on hold after volunteer becomes ill

The company says it is working to expedite the review of the single event to minimize any potential impact on the trial timeline. 

Susan Morse, Managing Editor

AstraZeneca, a major pharmaceutical company in the testing phase for a COVID-19 vaccine, put its clinical drug trial temporarily on hold after a volunteer became ill.

On Wednesday, the company said the event had triggered a standard review process. A committee of independent experts will review the safety data of the single event of an unexplained illness that occurred in the U.K. Phase III trial.

No other information on the illness or the volunteer's condition has been released.

"This is a routine action which has to happen whenever there is a potentially unexplained illness in one of the trials, while it is investigated, ensuring we maintain the integrity of the trials," AstraZeneca said.

AstraZeneca is working to expedite the review of the single event to minimize any potential impact on the trial timeline. 

The pause is temporary, according to CEO Pascal Soriot.


The United Kingdom-based AstraZeneca was leading the trial for a COVID-19 vaccine as regulatory sponsor, according to the National Institutes of Health. On August 31, the NIH announced a multi-site Phase 3 clinical trial to evaluate an investigational COVID-19 vaccine known as AZD1222. 

The trial was expected to enroll approximately 30,000 adult volunteers at 80 sites in the United States. 

AZD1222 was co-invented by the University of Oxford and its spin-out company, Vaccitech, AstraZeneca said. 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 later infects the body.


Finding a vaccine for COVID-19 has become a political issue, as President Donald Trump has said one would be available by the time of the November 3 presidential election.

AstraZeneca has said nine CEOs have signed a pledge to continue to make the safety and well-being of vaccinated individuals the top priority in development of the first COVID-19 vaccines.

The CEOs of AstraZeneca, BioNTech, GlaxoSmithKline, Johnson & Johnson, Merck (known as MSD outside the United States and Canada), Moderna, Novavax, Pfizer and Sanofi outlined a united commitment to uphold the integrity of the scientific process as they work towards potential global regulatory filings and approvals of the first COVID-19 vaccines.


"At AstraZeneca we put science, safety and the interests of society at the heart of our work," CEO Pascal Soriot said. "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."

Twitter: @SusanJMorse
Email the writer: