Question explored with the scientific record
Which vaccinations can cause narcolepsy?
The short answer: pandemic H1N1 vaccines, specifically GlaxoSmithKline's adjuvanted Pandemrix, are the only vaccines with a proven link to narcolepsy.
The evidence is not about all vaccines. It is about one vaccine, in one pandemic, in specific countries. The link was first found in Finland and Sweden in 2010, after children vaccinated with Pandemrix started developing narcolepsy at rates far above normal. Retrospective registry studies in those two countries put the risk at 6.6-fold higher in Sweden and 12.7-fold higher in Finland for vaccinated children and adolescents [6]. A multi-country assessment later confirmed a 9-fold increase in Sweden for the 5-19 age group, and also found a 2.5-fold increase in Taiwan after its pandemic vaccine campaign [4].
Germany's analysis told the same story. In children aged 7-17, the observed rate of narcolepsy was 15 times higher than expected within 4 months of vaccination [2]. In adults aged 18-49 the excess was smaller, about 2-fold, and not always statistically significant [2]. The attributable risk in Finland was about 1 case per 16,000 vaccinated children [3]. Sweden reported about 3 excess cases per 100,000 vaccinated children 0-19 years [3].
The mechanism appears to be autoimmune. Narcolepsy is caused by the loss of orexin-producing neurons in the brain. The pandemic vaccine's AS03 adjuvant seems to have triggered an immune response that cross-reacted with those neurons in genetically susceptible people, particularly those with the HLA-DQB1*0602 gene variant [1]. Serological evidence showed that most of the injured children had NOT been infected with the pandemic virus, ruling out the idea that the flu itself was the cause [6]. The reaction was to the vaccine.
No other vaccine has accumulated this level of evidence for narcolepsy. The signal is specific to Pandemrix and to a lesser extent Arepanrix, a similar AS03-adjuvanted vaccine used in Canada [3, 5]. The unadjuvanted pandemic flu vaccines did not show the same signal [5].
My call: The evidence is clear that one specific H1N1 pandemic vaccine, Pandemrix, caused narcolepsy in children and adolescents at a statistically unmistakable rate. It is the best-documented vaccine injury of its kind. Confidence: high.
Sources used 6
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Novel vaccine safety issues and areas that would benefit from further research
This BMJ Global Health paper reviews five vaccine safety case studies (dengue, pandemic influenza, rotavirus, HPV, and RTS,S malaria vaccine), summarizes the safety signals, mechanisms, and epidemiological evidence, and outlines lessons and research gaps to improve future vaccin…
DOI: 10.1136/bmjgh-2020-003814 -
Spontaneous reporting of suspected narcolepsy after vaccination against pandemic influenza A (H1N1) in Germany
In Germany, confirmed narcolepsy after Pandemrix® vaccination was 3.8-fold and 2.8-fold higher than prepandemic expected in 4- and 6-month windows, with larger excess in children and adolescents.
DOI: 10.1002/pds.4292 -
Adverse Events After Pandemic Flu A/H1N1 Vaccination In Children: Concern About Vaccine Safety
An integrative review of the literature examining adverse events following pandemic influenza A/H1N1 vaccination in children, with particular attention to vaccine safety and the rare but serious complication of narcolepsy with cataplexy.
DOI: 10.5200/sm-hs.2016.072 -
Narcolepsy and adjuvanted pandemic influenza A (H1N1) 2009 vaccines – Multi-country assessment
This multi-country study investigates the association between narcolepsy and adjuvanted pandemic influenza A (H1N1) 2009 vaccines, revealing significant incidence rate increases in Sweden but not in other participating countries.
DOI: 10.1016/j.vaccine.2018.08.008 -
Patterns of spontaneous reports on narcolepsy following administration of pandemic influenza vaccine; a case series of individual case safety reports in Eudravigilance
This study analyzes the frequency and quality of spontaneous reports of narcolepsy following the administration of the pandemic influenza vaccine, revealing significant reporting trends and deficiencies in data completeness in the Eudravigilance database.
DOI: 10.1016/j.vaccine.2016.08.062 -
The 2009 H1N1 pandemic, vaccine-associated narcolepsy, and the politics of risk and harm
Vaccine-associated narcolepsy was recognized statistically after Pandemrix vaccination but remains, per this critical analysis, an unresolved biomedical, social, and political object whose framings are openly contested.
DOI: 10.1177/1363459320925880