2nd COVID-19 vaccine trial paused over unexplained illness

A late-stage study of Johnson & Johnson’s COVID-19 vaccine candidate has been paused while the company investigates whether a study participant’s “unexplained illness” is related to the shot.

The company said in a statement Monday evening that illnesses, accidents and other so-called adverse events “are an expected part of any clinical study, especially large studies,” but that its physicians and a safety monitoring panel would try to determine what might have caused the illness.

The pause is at least the second such hold to occur among several vaccines that have reached large-scale final tests in the U.S.

The company declined to reveal any more details about the illness, citing the participant’s privacy.