Johnson & Johnson Halts COVID-19 Vaccination Trial Over ‘Unexplained Illness’

Johnson & Johnson announced in a statement on Monday that the clinical trial for its COVID-19 vaccination has been put on hold due to an unexplained illness in one of the study participants.

“Adverse events – illnesses, accidents, etc. – even those that are serious, are an expected part of any clinical study, especially large studies,” the statement read.

First reported by STAT, the trial’s “pausing rule” has been met, which means that no more patients will receive the vaccine, and enrollment for the trial has been closed. Johnson & Johnson stressed that the trial is not under any regulatory hold but did not provide a timeline for when the trial can resume. 

“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. 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,” the statement continued.

“Serious adverse events (SAEs) are not uncommon in clinical trials, and the number of SAEs can reasonably be expected to increase in trials involving large numbers of participants.”

Citing the privacy of the individual and the need to find out more information about the illness, the company will not provide any more information at this time. 

This is the second Phase 3 COVID-19 vaccine trial that had to put on pause. Last month, AstraZeneca put their trial on hold over an adverse reaction in a British volunteer, according to CNN. The trial has resumed in other countries but remains on hold in the U.S.