AstraZeneca COVID-19 vaccine tests stop after participant develops neurological issue

The study participant in late-stage testing reported symptoms consistent with transverse myelitis, a rare inflammation of the spinal cord, said AstraZeneca spokesman Matthew Kent.

“We don’t know if it is (transverse myelitis),” Kent said. “More tests are being done now as part of the follow-up.”

AstraZeneca said its “standard review process triggered a pause to vaccination to allow review of safety data.” It did not provide any details other than to say a single participant had an “unexplained illness.”

The vaccine, which AstraZeneca is developing with researchers from the University of Oxford, has been viewed as one of the leading candidates. The partners are aiming to enroll as many as 50,000 participants for late-stage trials that are underway in the U.K., the U.S., Brazil and South Africa, with others planned for Japan and Russia.

The company says an independent committee is currently reviewing the study’s safety data to determine if and when research can resume.

The study was previously stopped in July for several days after a participant who got the vaccine developed neurological symptoms. In that case, the issue turned out to be an undiagnosed case of multiple sclerosis that was unrelated to the vaccine.