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AstraZeneca Phase 3 Trials Paused Due To Safety Concerns, UC San Diego Arm Of Study Delayed

The type of needle doctors use to administer shots such as vaccines is shown in this undated photo illustration.
Nicole Tyau/inewsource
The type of needle doctors use to administer shots such as vaccines is shown in this undated photo illustration.

UK-based biotech company AstraZeneca earlier this week paused its phase 3 clinical trials for a COVID-19 vaccine due to a participant safety concern.

Now, a data safety review board is investigating whether the illness is connected to the vaccine.

AstraZeneca Phase 3 Trials Paused Due To Safety Concerns, UC San Diego Arm Of Study Delayed
Listen to this story by Shalina Chatlani.

David Smith, an infectious disease doctor at UC San Diego, said phase 3 clinical trials are an opportunity for vaccine developers to see whether any specific health concerns for patients. In this case, one patient in the AstraZeneca trial had an unexplained illness.


“We have to do our due diligence and figure out both efficacy and safety,” Smith said “And this trial has this thing called a data safety monitoring board. And it's a group of researchers, statisticians, scientists, physicians who get to see the data unblinded. They're the only people in the world that actually get to see it.”

“And here they said if there is some sort of neurologic complication, it doesn't matter where, we're going to stop the trial and look and see," Smith said.

And what the team is reviewing is a case of myelitis in one of the patients. That’s a condition usually associated with polio.

“So it causes this basically a destruction or it kills a piece of the spinal cord where people could actually become paralyzed,” Smith said.

Smith says it’s still unclear whether the vaccine caused it or whether the patient already had the condition.


In a Sept. 9 press release, AstraZeneca wrote, “in large clinical trials, illnesses will happen by chance and must be independently reviewed. AstraZeneca is working to expedite the review of the single event to minimize any potential impact on the trial timeline.”

AstraZeneca has gained international renown for being one of the leaders in coronavirus vaccine development. In June, the company announced that it had reached a deal with several European countries to supply hundreds of millions of vaccine doses before the end of the year. Though, with the trial on pause, it’s unclear when that will happen.

Smith says he’s confident that the company will do its due diligence as it ensures safety for trial participants. Still, President Donald Trump has said he wants companies to fast track a vaccine for before election day in November.

“I never thought we were going to get a vaccine by Nov. 1,” Smith said. “My hope has borne fruit that these trials are conducted in a very safe way. So we still have these safeguards. This data safety data monitoring board says we're going to look at it very closely. And if we see any safety signals, we're stopping it. We're stopping it and taking a deep dive.”

Smith says the pause really just means the developer is doing exactly what it should be: checking for safety and efficacy.

CNN reported Tuesday that major drug companies, including Pfizer and Johnson & Johnson, working on a COVID-19 vaccine issued a public letter vowing not to bow to political pressure from Trump; that any vaccine will go through rigorous trials necessary to ensure safety and effectiveness.

In the meantime, Smith says it’s really important for scientists to develop antivirals and other coronavirus treatments, as a vaccine won’t be a catchall solution to the pandemic.

“People are still going to get sick with coronavirus. So the next thing that we need, in my opinion, are really good treatments at the moment. We have some treatments in the hospital that can keep people from dying,” Smith said.

UC San Diego had planned to participate in the AstraZeneca trials, but that’s also on hold for now. Smith confirmed that no San Diegan has been given the AstraZeneca vaccine yet.