COVID-19 Vaccine Trial Put On Hold Because of Possible Adverse Reaction

One of the leaders in the race to develop a COVID-19 vaccine has suffered a setback because a participant in the vaccine’s phase 3 trial developed a serious condition that might be related to vaccine.

The New York Times is reporting that a study volunteer in the U.K. developed transverse myelitis, a condition characterized by inflammation of the spinal cord. According to an National Institute of Neurological Disorders and Stroke fact sheet about transverse myelitis, the causes can include a number of different autoimmune disorders, an abnormal immune response to cancer, and viral, bacterial, and fungal infections.

Stat broke the news about the possible adverse reaction and the pause in the enrollment in the AstraZeneca's phases 3 study yesterday.

In response to Stat's story, AstraZeneca put out a statement that said it had voluntarily paused vaccination. The statement described the stoppage as a “routine action, which has to happen whenever there is a potentially unexplained illness," and cautioned that in "large trials illnesses will happen by chance."

AstraZeneca announced on Aug. 31 that it was starting to enroll study volunteers in the United States with a goal of recruiting up to 30,000 participants. The trial is designed so some people are randomized to get two doses of the vaccine — known temporarily as AZD1222 — four weeks apart and others, a saline solution.

The Times reported that the vaccine, which was developed by University of Oxford researchers, is in phase 2/3 trials in England and phase 3 trials in Brazil, South African and the United States.