'Unexplained illness' forces Johnson & Johnson to pause COVID-19 vaccine study: report
Doctor holding vaccine. (AFP)

On Monday, CNN reported that the drug manufacturer Johnson & Johnson has been forced to temporarily halt ENSEMBLE — its current round of COVID-19 vaccine trials — due to an adverse event reported by one of the participants.

"Following our guidelines, the participant's illness is being reviewed and evaluated by the ENSEMBLE independent Data Safety Monitoring Board (DSMB) as well as our internal clinical and safety physicians," said the company in a statement.

"The company did not say what the unexplained illness was, but one point of clinical trials is to find out if vaccines cause dangerous side effects," reported Maggie Fox. "Trials are stopped when they pop up while doctors check to see if the illness can be linked to the vaccine or is a coincidence."

Recently, AstraZeneca, a rival company also working on a COVID-19 vaccine, also had to shut down one of its trials due to a mystery illness. That trial was resumed in mid-September after researchers concluded the illness was not linked to the vaccine.