At the end of March 2011, an MPA press release stated: "Results from a Swedish registry based cohort study indicate a 4-fold increased risk of narcolepsy in children and adolescents below the age of 20 vaccinated with Pandemrix, compared to children of the same age that were not vaccinated."[27] The same study found no increased risk in adults who were vaccinated with Pandemrix. While cautioning that the increase in risk for children is still uncertain in magnitude, it recommends they not be vaccinated.