(NewsNation Now) — AstraZeneca has paused its COVID-19 clinical trial twice, a spokesperson confirmed Wednesday.

According to the spokesperson, the clinical trial was briefly paused in July when one volunteer in the trial was confirmed to have a previously undiagnosed case of multiple sclerosis.

The spokesperson denied a report published Wednesday that claimed the AstraZeneca CEO stated the current pause in the COVID-19 vaccine clinical trial was due to a participant suffering from transverse myelitis, which is inflammation of the spinal cord.

“He stated that there is no final diagnosis and that there will not be one until more tests are carried out. Those tests will be delivered to an independent safety committee that will review the event and establish a final diagnosis,” the spokesperson said.

Read the full statement from AstraZeneca to NewsNationNow.com below:

“Reports claiming to be based on comments made earlier today by our CEO stating that we have confirmed that a participant in our clinical trial suffered from transverse myelitis are incorrect. He stated that there is no final diagnosis and that there will not be one until more tests are carried out. Those tests will be delivered to an independent safety committee that will review the event and establish a final diagnosis. We can also confirm that there was a brief trial pause in July while a safety review took place after one volunteer was confirmed to have an undiagnosed case of multiple sclerosis, which the independent panel concluded was unrelated to the vaccine.”

Two other vaccines are in huge, final-stage tests in the United States, one made by Moderna Inc. and the other by Pfizer and Germany’s BioNTech. Those two vaccines work differently than AstraZeneca’s, and the studies already have recruited about two-thirds of the needed volunteers.

Temporary holds of large medical studies aren’t unusual, and investigating any serious or unexpected reaction is a mandatory part of safety testing. AstraZeneca pointed out that it’s possible the problem could be a coincidence; illnesses of all sorts could arise in studies of thousands of people.

Dr. Deborah Birx, a member of the White House Coronavirus Task Force previously told NewsNation that there are no shortcuts when developing a coronavirus vaccine.

“American public should be assured. There are no short cuts in the vaccine development part,” Birx said. She says none of the vaccine candidates is skipping out on the science.

The Associated Press contributed to this report.