After one of its volunteers fell sick with an unexplained illness, the clinical trial testing AstraZeneca's experimental COVID-19 vaccine has been temporarily put on hold.
There's no available evidence suggesting that the illness is linked to the vaccine, CNN reports. But AstraZeneca still needs to investigate and review its safety data before the trial can proceed. Otherwise, the researchers won't know whether the volunteer just happened to get sick or if the vaccine has more side effects than they thought.
"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 in a statement sent to CNN.
As vaccines are developed and tested on an accelerated timeline to meet the urgency of the coronavirus pandemic, one of the biggest challenges will be making sure the public trusts whichever one gets distributed.
Of course, it's just as important to make sure any vaccines are indeed safe. Russia, China and a group of MIT researchers have all sidestepped the conventional clinical trial process to administer experimental vaccines, but AstraZeneca and other pharma companies recently signed a pledge to not release any vaccines for the virus until they've been thoroughly tested for any safety issues.
It's not clear whether AstraZeneca or a regulatory body made the call to pause the clinical trial, but doing so is an important part of making sure the experimental vaccine isn't just rushed out of the gate.
"In large trials, illnesses will happen by chance but must be independently reviewed to check this carefully," reads the AstraZeneca statement. "We are working to expedite the review of the single event to minimize any potential impact on the trial timeline. We are committed to the safety of our participants and the highest standards of conduct in our trials."