About particularly that, Wikipedia says "In 2018, a multinational study including Centers for Disease Control and Prevention scientists published safety data on adjuvanted pH1N1 vaccines. Sweden was the only country where increased narcolepsy IRs were found in the period after vaccination campaigns. The ability of the researchers to evaluate the Pandremix brand vaccine was limited.", but you can read other ones as well here: https://en.wikipedia.org/wiki/Pandemrix#Narcolepsy
It is quite interesting.