Johnson & Johnson halted clinical trials of its Covid-19 vaccine after a participant fell ill, the second time that a front-runner developer has paused testing in the race to create a viable immunization against the virus.
The participant’s illness is being evaluated, the New Brunswick, New Jersey-based company said late Monday, adding that it would share information after further investigation. J&J shares fell 2.4% in trading before U.S. exchanges opened. The vaccine is undergoing tests in as many as 60,000 volunteers from Peru to South Africa.
J&J is racing along with rivals such as Moderna Inc., Pfizer Inc. and AstraZeneca Plc to deliver a shot to help blunt the pandemic. Drugmakers must balance time pressures -- especially as coronavirus cases set new records -- with safety considerations in the crucial last stage of testing.