The European Union's drug regulator said on Thursday it had started a rolling review of the inactivated-virus COVID-19 vaccine from French biotech firm Valneva, weeks after the EU signed a deal with the company for supplies of the shot.

The decision to start the real-time review was based on preliminary studies that suggest the vaccine, VLA2001, triggers an antibody response against the coronavirus, the European Medicines Agency (EMA) said.