Johnson & Johnson has paused clinical trials of its COVID-19 vaccine candidate due to an unexplained illness in a study participant, delaying one of the highest profile efforts to contain the global pandemic.
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The move comes around a month after AstraZeneca also suspended trials of its experimental coronavirus vaccine — which uses a similar technology — due to a participant falling ill.
J&J said on Monday the illness was being reviewed by an independent data and safety monitoring board as well as the U.S. group’s clinical and safety physicians
The company, which reports quarterly financial results on Tuesday morning, said such pauses are normal in big trials, which can include tens of thousands of people. It added the voluntary “study pause” in giving doses of the vaccine candidate was different from a “regulatory hold” imposed by health authorities.
AstraZeneca last month paused late-stage trials of its experimental coronavirus vaccine developed with the University of Oxford due to an unexplained illness in a British study participant.
While AstraZeneca’s trials in Britain, Brazil, South Africa and India have since resumed, its U.S. trial is still on hold, pending a regulatory review.
The J&J and AstraZeneca vaccines are both based on a so-called adenovirus, a harmless modified virus that instructs human cells to produce vaccine proteins.
Safety concerns
They are both also part of the U.S. government’s Operation Warp Speed programme to support vaccine development.
“This could be a second case of adenoviral vaccine to spur safety concerns,” said Bryan Garnier analyst Olga Smolentseva.
Companies are required to investigate any serious or unexpected reaction that occurs during drug testing. Given that such tests are done on tens of thousands of people, some medical problems are a coincidence. In fact, one of the first steps the company said it will take is to determine if the person received the vaccine or a placebo.
The halt was first reported by the health news site STAT.
Final-stage testing of a vaccine made by AstraZeneca and Oxford University remains on hold in the US as officials examine whether an illness in its trial poses a safety risk. That trial was stopped when a woman developed severe neurological symptoms consistent with transverse myelitis, a rare inflammation of the spinal cord, the company has said. That company’s testing has restarted elsewhere.
Johnson & Johnson was aiming to enroll 60,000 volunteers to prove if its single-dose approach is safe and protects against the coronavirus. Other vaccine candidates in the U.S. require two shots.