Late-stage clinical trials for Johnson & Johnson’s (J&J) coronavirus vaccine have been halted after one person in the study developed an “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 company said in a press release.
The company did not provide further details regarding the illness developed by the participant nor on their condition, citing personal privacy concerns.
“We’re also learning more about this participant’s illness, and it’s important to have all the facts before we share additional information,” the company wrote.
The participant will be medically examined by the pharma firm’s physicians and their illness will be evaluated by the trial’s Data Safety Monitoring Board, an independent body surveying participants’ safety throughout the trials.
The pause will also mean that future recruiting of new study participants will be paused until the review of the illness in question is completed.
The company stressed that study pauses were a common and expected occurrence during not always publicly communicated on by firms, and stressed that they were not the same as a regulatory hold, which is a paused ordered by a national health authority.
For the start of Phase 3, the last stage in the development on a vaccine, J&J’s ENSEMBLE double-blind trials aimed to recruit 60,000 volunteers with and without comorbidities in Argentina, Brazil, Chile, Colombia, Mexico, Peru, South Africa and the United States.
When an illness or adverse effect appears, the company told medical news outlet Statnews that it is not immediately clear whether the participant in question received a placebo or an actual dose of the candidate vaccine.
In early August, AstraZeneca also paused its Phase 3 trials —the last stage in the development of a vaccine— after one study participant in the UK developed a “serious side effect.” The trials have resumed since, except in the United States, according to Statnews.