An increased incidence of narcolepsy in children was detected in Scandinavian 
countries where pandemic H1N1 influenza ASO3-adjuvanted vaccine was used. A 
campaign of vaccination against pandemic H1N1 influenza was implemented in 
France using both ASO3-adjuvanted and non-adjuvanted vaccines. As part of a 
study considering all-type narcolepsy, we investigated the association between 
H1N1 vaccination and narcolepsy with cataplexy in children and adults compared 
with matched controls; and compared the phenotype of narcolepsy with cataplexy 
according to exposure to the H1N1 vaccination. Patients with 
narcolepsy-cataplexy were included from 14 expert centres in France. Date of 
diagnosis constituted the index date. Validation of cases was performed by 
independent experts using the Brighton collaboration criteria. Up to four 
controls were individually matched to cases according to age, gender and 
geographic location. A structured telephone interview was performed to collect 
information on medical history, past infections and vaccinations. Eighty-five 
cases with narcolepsy-cataplexy were included; 23 being further excluded 
regarding eligibility criteria. Of the 62 eligible cases, 59 (64% males, 57.6% 
children) could be matched with 135 control subjects. H1N1 vaccination was 
associated with narcolepsy-cataplexy with an odds ratio of 6.5 (2.1-19.9) in 
subjects aged<18 years, and 4.7 (1.6-13.9) in those aged 18 and over. 
Sensitivity analyses considering date of referral for diagnosis or the date of 
onset of symptoms as the index date gave similar results, as did analyses 
focusing only on exposure to ASO3-adjuvanted vaccine. Slight differences were 
found when comparing cases with narcolepsy-cataplexy exposed to H1N1 vaccination 
(n=32; mostly AS03-adjuvanted vaccine, n=28) to non-exposed cases (n=30), 
including shorter delay of diagnosis and a higher number of sleep onset rapid 
eye movement periods for exposed cases. No difference was found regarding 
history of infections. In this sub-analysis, H1N1 vaccination was strongly 
associated with an increased risk of narcolepsy-cataplexy in both children and 
adults in France. Even if, as in every observational study, the possibility that 
some biases participated in the association cannot be completely ruled out, the 
associations appeared robust to sensitivity analyses, and a specific analysis 
focusing on ASO3-adjuvanted vaccine found similar increase.