During their study, US researchers analyzed the data of 23 million Americans who received the so-called monovalent inactivated vaccine against H1N1.
The study showed that within three months of the vaccination, Guillain-Barre syndrome was recorded in 77 cases.
Pandemrix, a vaccine that relies on a booster to prime the immune system against the H1N1 virus was not used during the American inoculation program.
But this was not the case in Sweden, England and Finland where Pandemrix was used and which led to an elevated risk of narcolepsy. Narcolepsy is known to cause drowsiness among its victims.
In Guillain-Barre syndrome, the body begins to attack nerves involved in movement and in certain cases other functions also get affected. It can also affect respiration.