AstraZeneca Announces Pause on COVID Vaccine Trials

British-Swedish international pharmaceutical company AstraZeneca has paused trials of its experimental COVID-19 vaccine after one of the participants became sick with what is possibly an adverse reaction to the shot. The inexplicable illness could completely hinder their efforts in the race to develop and market a viable vaccine for the coronavirus pandemic.

The company issued a statement saying it’s too soon to determine if the illness was caused by the vaccine and they need time for their researchers to examine the medical data to analyze the diagnosis specifics.

AstraZeneca has been partnering with University of Oxford researchers with the goal of enrolling up to 50,000 people in vaccine trials which they have already begun in the US, UK, South Africa and Brazil, with plans to include Russia and Japan trials in the near future.

News of the vaccine trials being halted caused market shares of the company to drop in London by nearly 3% on Wednesday. With a valuation of around $140 billion, AstraZeneca is the largest company on the UK’s FTSE-100 Index. Rival vaccine makers BioNtech SE and Moderna, Inc., saw late trading gains in the New York market on Tuesday.