Johnson & Johnson has paused its COVID-19 vaccine trial after a participant experienced an “unexplained illness.”
The company announced Monday, Oct. 12, in a statement sent to researchers that the study had been paused and that the online enrollment system had been closed. In addition, the statement said that the data and safety monitoring board, which is intended to watch over the health of the 60,000 patients involved, had been summoned.
Phase 3 of the ENSEMBLE trial was paused due to “an unexplained illness in a study participant,” the company said in a statement.
“We must respect this participant’s privacy. We’re also learning more about this participant’s illness, and it’s important to have all the facts before we share additional information,” Johnson & Johnson said. The company also noted that it is not always immediately clear in a placebo-controlled study whether a participant received a placebo or the study treatment.
In the statement, the company also clarified the difference between a study pause and a regulatory hold. A regulatory hold can last significantly longer than a pause and is a formal protocol mandated by a health authority such as the FDA. In contrast, the public is often not notified of a study pause, which are not rare and may only last for a few days. The company said that adverse events like illnesses are to be expected during a clinical trial. Dr. Ashish Jha, the dean of the Brown University School of Public Health, who does not appear to be affiliated with the study told CNN’s Chris Cuomo, “Within that trial you’d expect a few pauses.”
“If we do a study of 60,000 people, that is a small village,” said an unnamed individual identified by STAT News as a source close to the study. “In a small village there are a lot of medical events that happen,” the source added.
The trial is concerned with evaluating whether Johnson & Johnson’s Janssen vaccine candidate can prevent symptomatic COVID-19 after a single dose. In addition to Janssen, a branch of Johnson & Johnson, the trial is being funded by the National Institute of Allergy and Infectious Diseases (NIAID), and the Biomedical Advanced Research and Development Authority (BARDA), part of the U.S. Department of Health and Human Services.
News of the study pause comes as the nation nears 8 million coronavirus cases, while the death toll stands at more than 215,000.