Johnson & Johnson second company to pause vaccine trial after unexplained illness

“We have temporarily paused further dosing in all our Covid-19 vaccine candidate clinical trials, including the Phase 3 ENSEMBLE trial, due to an unexplained illness in a study participant,”

The pause means the enrolment system has been closed for the 60,000-patient clinical trial while the independent patient safety committee is convened.

J&J said that serious adverse events (SAEs), such as accidents or illnesses, are “an expected part of any clinical study, especially large studies”; but that its physicians are and a safety monitoring panel would try to determine what might have caused the illness. Company guidelines allow them to pause a study to determine if the SAE was related to the drug in question and whether to resume the study.

This is the second such hold on large-scale final vaccine tests in the U.S. Temporary stoppages are considered a relatively common accurate in large medical studies but are often not revealed to the public. Companies are required to investigate any serious or unexpected reaction that occurs during drug testing.

Final-stage testing of a vaccine made by AstraZeneca and Oxford University remains on hold in the U.S. as officials examine whether an illness in its trial poses a safety risk. That trial was stopped when a woman developed severe neurological symptoms consistent with transverse myelitis, a rare inflammation of the spinal cord, the company has said. That company’s testing has restarted elsewhere.

Sometimes medical problems are a mere coincidence and the company must first determine if a sick participate received the placebo or the vaccine.

Citing patient confidentiality the company would not reveal any more details about the illness.