AstraZeneca Plc stopped giving shots of its experimental coronavirus vaccine after a person participating in one of the company’s studies got sick, a potential adverse reaction that could delay or derail efforts to speed an immunization against COVID-19 for the world.
The pause stemmed from a standard review of the company’s vaccine trials after one person developed an unexplained illness, AstraZeneca said in a statement. The move was intended to give researchers time to examine safety data while maintaining the integrity of the trials, the company said.
The vaccine, which AstraZeneca is developing with researchers from the University of Oxford, has been viewed as one of the leading candidates to reach the market. The decision to tap the brakes jolted investors, sending AstraZeneca’s U.S.-traded shares down sharply, while boosting the stocks of some rivals developing different potential COVID-19 shots.