https://www.siliconvalley.com/2020/10/12/2nd-covid-19-vaccine-trial-paused-over-unexplained-illness/

NEW BRUNSWICK, N.J. (AP) — 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.