On Wednesday, Italy banned the sales and use of four anti-influenza vaccines produced by Novartis pending tests for possible side effects.

The Swiss health watchdog later followed suit, issuing a precautionary halt to deliveries of the vaccines Agrippal and Fluad, which are manufactured in Italy.

Novartis said the move by the Italian health ministry followed a report by the drugmaker of small particles in the vaccines. It said it had already provided the ministry with an assessment confirming the safety of the vaccines.

"Novartis confirms that these particles can occur in the vaccine manufacturing process and is confident that there is no impact on the safety or efficacy of the vaccine," it said in a statement.

The company said it would continue to cooperate with Italian health authorities to understand the reasons for their decision, and remained committed to patient safety.

(Reporting by Caroline Copley; Editing by Daniel Magnowski)

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