Finnish health officials say they have found an increased risk of narcolepsy among four to 19-year-olds who were given vaccines against swine flu.

The National Narcolepsy Task Force says a preliminary study indicates that children vaccinated with Pandemrix "contributed to the observed increase in incidence of narcolepsy" compared to those who were not vaccinated in the same age group.

The study published by Finland's National Institute for Health and Welfare today said that "the most likely explanation is that the increase in narcolepsy is by joint effect of the vaccine and some other factor".

In August, the European Medicines Agency said it was investigating a possible link between the swine flu vaccine and narcolepsy, a rare disorder that causes people to suddenly fall asleep.

Sign up to our free newsletters

Get the best updates straight to your inbox:
Please select at least one mailing list.

You can unsubscribe at any time by clicking the link in the footer of our emails. We use Mailchimp as our marketing platform. By subscribing, you acknowledge that your information will be transferred to Mailchimp for processing.