Valneva (VALN) said Monday that France's national public health agency suspended the use of single-dose chikungunya vaccine Ixchiq in persons at least 65 years old after three cases of serious adverse events, including one death.

The company said "causality has not been definitively established" and the suspension will remain in place pending further investigation.

The serious adverse events, which were reported through the country's pharmacovigilance system, involved individuals over 80 years old with comorbidities who received the vaccine, according to the company.

The vaccine is still recommended for use in individuals 18 to 64 years old in France, Valneva said.

Shares of Valneva were down 7.6% in recent trading.

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