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Finland Pandemrix childhood narcolepsy cohort (Nohynek)
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Design notes & limitations. Population registry-linkage cohort covering all Finnish children in the birth range, comparing narcolepsy incidence between Pandemrix-vaccinated and unvaccinated children (vaccine coverage 75%). Included to span the vaccine trigger class: the strongest example of an immune-mediated (autoimmune) post-exposure sequela with a defined denominator and an unvaccinated comparator. Of 67 confirmed cases, 46 vaccinated and 7 unvaccinated entered the primary analysis.
Identity & trigger
- Cohort id
nohynek-2012-pandemrix-narcolepsy- Aliases
- Finnish AS03/H1N1 vaccine narcolepsy cohort
- Outbreak / event
- 2009 H1N1 pandemic vaccination campaign (Finland)
- Pathogen
- Pandemrix (AS03-adjuvanted H1N1 influenza vaccine) (Vaccine)
- Exposure ascertainment
- registry code
Design
- Design
- Registry linkage
- Denominator defined
- Yes
- Denominator method
- All children living in Finland born 1 Jan 1991 - 31 Dec 2005, with vaccination status from the national vaccination registry and narcolepsy cases from national health registries.
- Recruitment
- population registry
- Time zero
- Receipt (or non-receipt) of AS03-adjuvanted Pandemrix H1N1 vaccine during the 2009-10 campaign (month)
- Control group
- Unexposed (unmatched)
Size & attrition
- Enrolled
- n/r
- Analysed / enrolled
- n/r
- Max follow-up (months)
- n/r
Biospecimens
- Specimens
- No
- Types
- none
- Acute-phase specimens
- N/A
- Biobank
- N/A
- External access
- N/A
Observations (1)
Events
9 per 100000 person-years Rate
- Measure
- Narcolepsy (incident) event:narcolepsy
- As worded
- “narcolepsy incidence 9.0 per 100 000 person-years in vaccinated vs 0.7 in unvaccinated children (rate ratio 12.7)”
- Population
- whole cohort · denominator Person-time · N=measured, not reported
- Timing
- None mo (Unspecified) · ref Not reported
- Method
- Unclear
- Comparator
- Unexposed (unmatched): 0.7 per 100000 person-years · RR RR 12.7 (6.1–30.8)
- Comparability signature
- 4285a87124 — measure event:narcolepsy · Unclear · ref Not reported · denom Person-time · Unspecified · Rate
- Provenance
- Results/Abstract (rate ratio 12.7, 95% CI 6.1-30.8) · Manual · verified OSMF research-tracker (web-verified against source) on 2026-07-20
Publications
- Nohynek H, Jokinen J, Partinen M, et al. (2012). AS03 adjuvanted AH1N1 vaccine associated with an abrupt increase in the incidence of childhood narcolepsy in Finland. PLoS ONE. PMID 22470453 · DOI 10.1371/journal.pone.0033536 primary
Provenance & verification
- Registration
- n/r
- Funders
- National Institute for Health and Welfare (THL), Finland
- Related cohorts
- none
- Symptom-inventory scope
- None
- Last verified
- 2026-07-20 — OSMF research-tracker (web-verified against source)