Oxford University partnered with AstraZeneca, a British-Swedish multinational pharmaceutical and biopharmaceutical company, to produce 2 billion doses of the vaccine.
In a statement Tuesday, a spokesperson from AstraZeneca said the company’s “standard review process triggered a pause to vaccination to allow review of safety data.”
“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,” the statement read.
The statement said in large trials illnesses happen “by chance,” but must be “independently reviewed to check this carefully.”
The company said it is “working to expedite the review of the single event” to “minimize any potential impact on the trial timeline.”
It’s likely the unexplained illness was serious enough to require hospitalization and not a mild side effect such as fever or muscle pain, said Deborah Fuller, a University of Washington researcher who is working on a different COVID-19 vaccine that has not yet started human testing.
“This is not something to be alarmed about,” Fuller said. Instead, it’s reassuring that the company is pausing the study to figure out what’s happening and carefully monitoring the health of study participants.
In a tweet Tuesday evening, Angela Rasmussen, a virologist at Columbia University, said this “may not be a big deal,” adding that the illness may be unrelated to the vaccine.
“But the important part is that this is why we do trials before rolling out a vaccine to the general public,” she wrote.
The Oxford University vaccine is one of many being tested to determine if they are safe and effective at treating the novel coronavirus.
Earlier on Tuesday, nine leading U.S. and European vaccine developers pledged to uphold scientific safety and efficacy standards for their experimental vaccines despite the urgency to contain the pandemic.
The companies, including AstraZeneca, Pfizer Inc and GlaxoSmithKline, issued what they called a “historic pledge” after a rise in concern that safety standards might slip in the face of political pressure to rush out a vaccine.
The companies said they would “uphold the integrity of the scientific process as they work towards potential global regulatory filings and approvals of the first COVID-19 vaccines.”
In a previous interview with Global News, Dr. Brian Dixon, a biology professor at the University of Waterloo and Canada Research Chair in Fish and Environmental Immunology, said third-stage trials are also when researchers determine if there are any severe side effects associated with the vaccine.
He said these can include excessive fever causing hospitalization or disability and excessive swelling causing meningitis or Kawasaki disease.
–With files from Reuters and The Associated Press