tetano
Editor, Senior Moderator
Vaccine. 2011 Sep 2. [Epub ahead of print]
Causality assessment of serious neurologic adverse events following 2009 H1N1 vaccination.
Williams SE, Pahud BA, Vellozzi C, Donofrio PD, Dekker CL, Halsey N, Klein NP, Baxter RP, Marchant CD, Larussa PS, Barnett ED, Tokars JI, McGeeney BE, Sparks RC, Aukes LL, Jakob K, Coronel S, Sejvar JJ, Slade BA, Edwards KM.
Source
Vanderbilt Vaccine Research Program, Vanderbilt University Medical Center, 1161 21st Ave. So. CCC 5323 MCN, Nashville, TN, United States.
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-Barr? 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. Published by Elsevier Ltd.
PMID:
21893148
[PubMed - as supplied by publisher]
http://www.ncbi.nlm.nih.gov/pubmed/21893148
Causality assessment of serious neurologic adverse events following 2009 H1N1 vaccination.
Williams SE, Pahud BA, Vellozzi C, Donofrio PD, Dekker CL, Halsey N, Klein NP, Baxter RP, Marchant CD, Larussa PS, Barnett ED, Tokars JI, McGeeney BE, Sparks RC, Aukes LL, Jakob K, Coronel S, Sejvar JJ, Slade BA, Edwards KM.
Source
Vanderbilt Vaccine Research Program, Vanderbilt University Medical Center, 1161 21st Ave. So. CCC 5323 MCN, Nashville, TN, United States.
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-Barr? 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. Published by Elsevier Ltd.
PMID:
21893148
[PubMed - as supplied by publisher]
http://www.ncbi.nlm.nih.gov/pubmed/21893148