Johnson & Johnson on Monday said that it had temporarily halted its Covid-19 vaccine trial because one of its participants had become sick.
“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 statement.
The pause means the online enrollment system has been closed for the 60,000-patient clinical trial while the independent patient safety committee is convened.
Two weeks ago, the company kicked off a final 60,000-person trial of a single-shot Covid-19 vaccine that potentially would simplify distribution of millions of doses compared with leading rivals using two doses.
Rival vaccines from Moderna Inc, Pfizer Inc and AstraZeneca all require two shots separated by several weeks, which make them much more difficult to administer.