Johnson & Johnson has paused clinical trials of its coronavirus vaccine candidate due to an unexplained illness in a study participant, delaying one of the highest profile efforts to contain the global pandemic. The move comes around a month after AstraZeneca AZN.L also suspended trials of its experimental coronavirus vaccine – which uses a similar technology – due to a participant falling ill.
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. They are both also part of the U.S. government’s Operation Warp Speed programme to support vaccine development.