Causality assessment of serious neurologic adverse events following 2009 H1N1 vaccination
- PMID: 21893148
- PMCID: PMC4860884
- DOI: 10.1016/j.vaccine.2011.08.093
Causality assessment of serious neurologic adverse events following 2009 H1N1 vaccination
Abstract
Background: Adverse events occurring after vaccination are routinely reported to the Vaccine Adverse Event Reporting System (VAERS). We studied serious adverse events (SAEs) of a neurologic nature reported after receipt of influenza A (H1N1) 2009 monovalent vaccine during the 2009-2010 influenza season. Investigators in the Clinical Immunization Safety Assessment (CISA) network sought to characterize these SAEs and to assess their possible causal relationship to vaccination.
Methods: Centers for Disease Control and Prevention (CDC) and Food and Drug Administration (FDA) physicians reviewed all SAE reports (as defined by the Code of Federal Regulations, 21CFR§314.80) after receipt of H1N1 vaccine reported to VAERS between October 1, 2009 and March 31, 2010. Non-fatal SAE reports with neurologic presentation were referred to CISA investigators, who requested and reviewed additional medical records and clinical information as available. CISA investigators assessed the causal relationship between vaccination and the event using modified WHO criteria as defined.
Results: 212 VAERS reports of non-fatal serious neurological events were referred for CISA review. Case reports were equally distributed by gender (50.9% female) with an age range of 6 months to 83 years (median 38 years). The most frequent diagnoses reviewed were: Guillain-Barré Syndrome (37.3%), seizures (10.8%), cranial neuropathy (5.7%), and acute disseminated encephalomyelitis (3.8%). Causality assessment resulted in classification of 72 events as "possibly" related (33%), 108 as "unlikely" related (51%), and 20 as "unrelated" (9%) to H1N1 vaccination; none were classified as "probable" or "definite" and 12 were unclassifiable (6%).
Conclusion: The absence of a specific test to indicate whether a vaccine component contributes to the pathogenesis of an event occurring within a biologically plausible time period makes assessing causality difficult. The development of standardized protocols for providers to use in evaluation of adverse events following immunization, and rapid identification and follow-up of VAERS reports could improve causality assessment.
Copyright © 2011 Elsevier Ltd. All rights reserved.
Figures
![Figure 1](https://cdn.statically.io/img/www.ncbi.nlm.nih.gov/pmc/articles/instance/4860884/bin/nihms776053f1.gif)
Similar articles
-
Events supposedly attributable to vaccination or immunization during pandemic influenza A (H1N1) vaccination campaigns in Latin America and the Caribbean.Vaccine. 2015 Jan 1;33(1):187-92. doi: 10.1016/j.vaccine.2014.10.070. Epub 2014 Nov 6. Vaccine. 2015. PMID: 25444798
-
Guillain-Barre syndrome, influenza, and influenza vaccination: the epidemiologic evidence.Clin Infect Dis. 2014 Apr;58(8):1149-55. doi: 10.1093/cid/ciu005. Epub 2014 Jan 9. Clin Infect Dis. 2014. PMID: 24415636 Review.
-
Clinical assessment of serious adverse events in children receiving 2009 H1N1 vaccination.Pediatr Infect Dis J. 2013 Feb;32(2):163-8. doi: 10.1097/INF.0b013e318271b90a. Pediatr Infect Dis J. 2013. PMID: 23334340
-
Autoimmune disorders after immunisation with Influenza A/H1N1 vaccines with and without adjuvant: EudraVigilance data and literature review.Vaccine. 2012 Nov 19;30(49):7123-9. doi: 10.1016/j.vaccine.2012.09.032. Epub 2012 Sep 26. Vaccine. 2012. PMID: 23022149 Review.
-
Safety of influenza A (H1N1) 2009 monovalent vaccines - United States, October 1-November 24, 2009.MMWR Morb Mortal Wkly Rep. 2009 Dec 11;58(48):1351-6. MMWR Morb Mortal Wkly Rep. 2009. PMID: 20010511
Cited by
-
Multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD) following COVID-19 vaccines: A systematic review.Rev Neurol (Paris). 2023 Apr;179(4):265-281. doi: 10.1016/j.neurol.2022.11.004. Epub 2023 Jan 17. Rev Neurol (Paris). 2023. PMID: 36658048 Free PMC article. Review.
-
Neurological sequelae of vaccines.Neurol Sci. 2023 May;44(5):1505-1513. doi: 10.1007/s10072-022-06581-z. Epub 2023 Jan 9. Neurol Sci. 2023. PMID: 36622478 Free PMC article. Review.
-
Acute abducens nerve palsy after COVID-19 vaccination in a young adult.Indian J Ophthalmol. 2021 Dec;69(12):3764-3766. doi: 10.4103/ijo.IJO_1968_21. Indian J Ophthalmol. 2021. PMID: 34827043 Free PMC article.
-
Revisiting Influenza Vaccination Exemption.Emerg Infect Dis. 2018 Oct;24(10):1947-1948. doi: 10.3201/eid2410.180304. Emerg Infect Dis. 2018. PMID: 30226178 Free PMC article.
-
Immunogenicity and predictors of response to a single dose trivalent seasonal influenza vaccine in multiple sclerosis patients receiving disease-modifying therapies.CNS Neurosci Ther. 2019 Feb;25(2):245-254. doi: 10.1111/cns.13034. Epub 2018 Jul 25. CNS Neurosci Ther. 2019. PMID: 30044050 Free PMC article.
References
-
- Butler D. Portrait of a year-old pandemic. Nature. 2010 Apr 22;464(7292):1112–3. - PubMed
-
- CDC. The 2009 H1N1 Pandemic: Summary Highlights, April 2009–April 2010, A Virus Emerges. 2010 [cited 11/24/2010]; Available from: http://www.cdc.gov/h1n1flu/cdcresponse.htm#virus_emerges.
-
- Hidiroglu S, Ay P, Topuzoglu A, Kalafat C, Karavus M. Resistance to vaccination: The attitudes and practices of primary healthcare workers confronting the H1N1 pandemic. Vaccine. 2010 Oct 14; - PubMed
-
- US Department of Health and Human Services. National Vaccine Advisory Committee Report on 2009 H1N1 Vaccine Safety Risk Assessment. [cited 1/13/2011]; Available from: http://www.hhs.gov/nvpo/nvac/reports/vsrawg_repot_may2010.html.
Publication types
MeSH terms
Substances
Grants and funding
LinkOut - more resources
Full Text Sources
Medical