Johnson & Johnson coronavirus vaccine trial paused after participant’s ‘unexplained illness’

Pause affects all the company’s trials, in which about 60,000 adults from across the globe were expected to participate

J&J had earlier said that the vaccine trial was expected to be over by the end of the year or the beginning of 2021

Johnson & Johnson says it has halted its coronavirus vaccine trials while it investigates the unexplained illness of one of its participants.  

“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 on Monday.  

The pause affects all the trials in which about 60,000 adults from across the globe were expected to participate.  

The pharmaceutical giant added that an independent data safety monitoring board is reviewing the subject’s illness. Serious adverse events (SAE) such as these are an expected part of any clinical trial and the study was paused in line with company guidelines, Johnson & Johnson (J&J) added. 

The company did not disclose the nature of the participant’s illness. “We must respect this participant’s privacy,” it said.  

J&J had earlier in September said that the vaccine trial was expected to be over by the end of the year or the beginning of 2021.  

According to the Wall Street Journal, the vaccine shots being used in the trial involve a weakened version of a common cold virus. It is then engineered to deliver genetic instructions, teaching the body’s cells to make a protein resembling one found on the surface of the coronavirus. This, in turn, induces the body’s immune system to build up defences against the coronavirus if a person is subsequently exposed to it.  

This is not the first time a major Covid-19 vaccine trial has been paused. In September, AstraZeneca halted late-stage trials of its experimental coronavirus vaccine, developed with the University of Oxford, due to an unexplained illness in a UK-based study participant. 

Globally, some 18,000 volunteers have received study vaccines as part of the AstraZeneca trial. The pause was triggered after a volunteer reportedly began suffering from neurological symptoms associated with a rare spinal inflammatory disorder called transverse myelitis. The study restarted a week afterwards in the UK, and in other countries since then, but remains on ice in the US.