This initiative was taken following the indication of a potential association between the 2009 pandemic influenza A(H1N1) monvalent vaccine and the occurrence of narcolepsy following reports, especially in children from Finland and Sweden.

In February 2011, ECDC published a report concerning a rise in narcolepsy in children and adolescents in some northern countries.

A four-fold increased incidence of narcolepsy in vaccinated children/adolescents compared to unvaccinated children was observed in this register-based cohort study.

In late March, 2011 ECDC reported that the Swedish Medical Product Agency published preliminary results from an on-going cohort study involving 5.3 million people, where 67% of children and adolescents and 51.0% of adults were vaccinated with Pandemrix.

The European Medicines Agency (EMA) was key in the Europe during the 2009 pandemic concerning the authorisation and the benefit – risk assessment of the novel pandemic vaccines.

This article comments on the importance of improving surveillance and doing quickly research on vaccine safety to maintain public trust.

ECDC has previously summarised information concerning the appearance of narcolepsy following the use of a specific pandemic vaccine (Pandemrix®) in children and adolescents in three European Countries.

Due to an association that was observed in the United States between a swine-flu based human influenza vaccine developed in 1976 and the disease acute polyneuropathy Guillain-Barré syndrome (GBS) (1,2), GBS was one of the adverse events that was monitored in Europe and North  America (3) following the 2009 influenza pandemic vaccination campaigns.