Immediate hypersensitivity reactions following monovalent 2009 pandemic influenza A (H1N1) vaccines: Reports to VAERS.
ABSTRACT Hypersensitivity disorders following vaccinations are a cause for concern.
To determine the type and rate by age, gender, and vaccine received for reported hypersensitivity reactions following monovalent 2009 pandemic influenza A (H1N1) vaccines.
A systematic review of reports to the Vaccine Adverse Event Reporting System (VAERS) following monovalent 2009 pandemic influenza A (H1N1) vaccines.
US Civilian reports following vaccine received from October 1, 2009 through May 31, 2010.
Age, gender, vaccines received, diagnoses, clinical signs, and treatment were reviewed by nurses and physicians with expertise in vaccine adverse events. A panel of experts, including seven allergists reviewed complex illnesses and those with conflicting evidence for classification of the event.
Of 1984 reports, 1286 were consistent with immediate hypersensitivity disorders and 701 were attributed to anxiety reactions, syncope, or other illnesses. The female-to-male ratio was ≥4:1 for persons 20-to-59 years of age, but approximately equal for children under 10. One hundred eleven reports met Brighton Collaboration criteria for anaphylaxis; only one-half received epinephrine for initial therapy. The overall rate of reported hypersensitivity reactions was 10.7 per million vaccine doses distributed, with a 2-fold higher rate for live vaccine.
Underreporting, especially of mild events, would result in an underestimate of the true rate of immediate hypersensitivity reactions. Selective reporting of events in adult females could have resulted in higher rates than reported for males.
Adult females may be at higher risk of hypersensitivity reactions after influenza vaccination than men. Although the risk of hypersensitivity reactions following 2009 pandemic influenza A (H1N1) vaccines was low, all clinics administering vaccines should be familiar with treatment guidelines for these adverse events, including the use of intramuscular epinephrine early in the course of serious hypersensitivity reactions.
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ABSTRACT: Biological (ie, sex) differences as well as cultural (ie, gender) norms influence the acceptance and efficacy of vaccines for males and females. These differences are often overlooked in the design and implementation of vaccination strategies. Using seasonal and pandemic influenza vaccines, we document profound differences between the sexes in the acceptance, correlates of protection, and adverse reactions following vaccination in both young and older adults. Females develop higher antibody responses, experience more adverse reactions to influenza vaccines, and show greater vaccine efficacy than males. Despite greater vaccine efficacy in females, both young and older females are often less likely to accept influenza vaccines than their male counterparts. Identification of the biological mechanisms, including the hormones and genes, that underlie differential responses to vaccination is necessary. We propose that vaccines should be matched to an individual's biological sex, which could involve systematically tailoring diverse types of FDA-approved influenza vaccines separately for males and females. One goal for vaccines designed to protect against influenza and even other infectious diseases should be to increase the correlates of protection in males and reduce adverse reactions in females in an effort to increase acceptance and vaccine-induced protection in both sexes.The Journal of Infectious Diseases 07/2014; 209 Suppl 3:S114-9. · 5.78 Impact Factor
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ABSTRACT: The most serious form of type I or IgE-mediated hypersensitivity reaction is anaphylaxis. A standardized case definition of anaphylaxis as an adverse event after immunization has been developed. Such reactions to vaccines, including influenza vaccine, are rare but potentially life-threatening. Until recently, all influenza vaccines were manufactured in eggs. Residual egg protein in the vaccines was thought to pose a risk to egg-allergic vaccine recipients. However, a large number of recent studies have demonstrated that egg-allergic recipients are no more likely than those without egg allergy to suffer such reactions. Published guidelines have been updated to recommend that patients with egg allergy receive annual influenza vaccination. Any patient who has an anaphylactic reaction to influenza vaccine should be carefully evaluated by an allergist for guidance on subsequent immunization.Expert Review of Vaccines 06/2014; · 4.22 Impact Factor