A British study finds that children and teens who were vaccinated during the 2009 swine flu outbreak are at increased risk for narcolepsy.
Narcolepsy is a sleep disorder that causes people to fall asleep unexpectedly, sometimes in the middle of a conversation. The flu vaccine in question was designed to protect against H1N1, and was never licensed for use in the United States.
Researchers looked at data from children and teens aged 4 to 18 who were treated at sleep centers and neurology centers in England, and concluded that receiving the Pandemrix vaccine was associated with a 14- to 16-fold increased risk of developing narcolepsy.
The authors of the new study wrote that the findings do indicate a “causal” link between the vaccine and the sleep disorder. They added, however, that the risk may still be overestimated and added that long-term monitoring of children and teens who received the vaccine is needed to determine the exact level of risk.