AstraZeneca Plc Chief Executive Officer Pascal Soriot said the coronavirus vaccine the company is developing with the University of Oxford could still be ready before the end of the year.

Speaking at an online conference Thursday, Soriot sought to reassure investors after the company and its partner confirmed earlier this week that they had temporarily stopped giving patients the experimental shot.

Astra shares rose 0.3 per cent in London, after earlier losses.

The trial was halted after a person in the U.K. who was participating in it got sick, triggering a review of safety data. It’s still not clear whether the patient has a condition called transverse myelitis, a suspected diagnosis, Soriot said.

The CEO said he can’t evaluate the length of the trial pause.