Shares of French drugmaker Valneva slumped more than 20% on Monday after the U.S. Food and Drug Administration suspended the licence for its chikungunya vaccine, Ixchiq, with immediate effect, citing serious safety concerns.

Less than three weeks after lifting a pause on the use of Valneva’s chikungunya vaccine Ixchiq, the FDA has done an about-face, banning the use of the shot in the United States. | Less than three weeks after lifting a pause on the use of Valneva’s chikungunya vaccine Ixchiq,

U.S. health authorities have suspended the license for the Ixchiq vaccine against the chikungunya virus following reports of "serious adverse events", the drug's French maker said on Monday.