Narkolepsi etter svineinfluensapandemien

I denne studien har forskere ved Folkehelseinstituttet undersøkt om influensa pandemi A(H1N1) i 2009/2010 og påfølgende vaksinasjon med Pandemrix hadde en sammenheng med utbrudd av narkolepsi eller hypersomni blant barn og unge i Norge. Blant personer under 30 år var det 3,6 % som fikk influensa under pandemien mens 41,9 % ble vaksinert. I løpet av perioden 2009 til 2012 var det henholdsvis 72 og 305 barn og unge som fikk diagnosen narkolepsi og hypersomni. Det var en svak sammenheng mellom influensa og økt risiko for narkolepsi og hypersomni i løpet av de første seks månedene etter infeksjonen, mens det ble funnet en sterk sammenheng mellom Pandemrix vaksinen og økt risiko for å utvikle narkolepsi.

 

Studien er publisert i Vaccine


Narcolepsy and hypersomnia in Norwegian children and young adults following the influenza A(H1N1) 2009 pandemic


Lill Trogstad, Inger Johanne Bakken, Nina Gunnes, Sara Ghaderi, Camilla Stoltenberg, Per Magnus, Siri E. Håberg


BACKGROUND: Associations between influenza infection and sleep disorders are poorly studied. We investigated if pandemic influenza infection or vaccination with Pandemrix in 2009/2010 was associated with narcolepsy or hypersomnia in children and young adults.

METHODS: We followed the Norwegian population under age 30 from January 2008 through December 2012 by linking national health registry data. Narcolepsy diagnoses were validated using hospital records. Risks of narcolepsy or hypersomnia were estimated as adjusted hazard ratios (HRs) in Cox regression models with influenza infection and vaccination as time-dependent exposures.

RESULTS: Among the 1,638,526 persons under age 30 in Norway in 2009, 3.6% received a physician diagnosis of influenza during the pandemic, while 41.9% were vaccinated against pandemic influenza. Between October 1st 2009 and December 31st 2012, 72 persons had onset of narcolepsy and 305 were diagnosed with hypersomnia. The risk of a sleep disorder was associated with infection during the first six months, adjusted HR 3.31 with 95% confidence interval [CI], 1.01-10.79 for narcolepsy and adjusted HR 3.13 (95% CI, 1.12-8.76) for hypersomnia. The risk of narcolepsy was strongly associated with vaccination during the first six months adjusted HR 17.21 (95% CI, 6.28-47.14), while the adjusted HR for hypersomnia was 1.54 (95% CI, 0.81-2.93).

CONCLUSIONS: The study confirms an increased HR of narcolepsy following pandemic vaccination. Slightly increased HRs of narcolepsy and hypersomnia are also seen after influenza infection. However, the role of infection should be viewed with caution due to underreporting of influenza.