Well, Pandemrix was never used in US. The mechanism of narcolepsy was quite interesting. Note that it was linked to surface proteins of the virus itself: http

Well, Pandemrix was never used in US. The mechanism of narcolepsy was quite interesting. Note that it was linked to surface proteins of the virus itself: https://www.newscientist.com/article/dn24772-flu-vaccine-helps-unravel-complex-causes-of-narcolepsy/ https://www.newscientist.com/article/dn24772-flu-vaccine-hel... The fact that GSK vaccine managed to replicate exactly those surface proteins exactly that way (I guess better than the virus itself?) was quite unlucky. Maybe that could have been caught in more extensive clinical trials (I don't know).