Administration of influenza vaccines to patients with egg allergy: Update for the 2010-2011 season

Seasonal split influenza vaccine induced IgE sensitization against influenza vaccine

Although anaphylaxis is an extremely rare vaccine-associated adverse event, it occurred in young children following administration of the 2011/12 seasonal split influenza vaccine, which contained 2-phenoxyethanol as the preservative. These children had high levels of IgE antibodies against influenza vaccine components. We herein investigated why these children were sensitized. One hundred and seventeen series of serum samples were obtained immediately before, and one month after the first and second immunizations with the HA split vaccine of 2011/12. Forty-two sequential serum samples were collected in the acute and convalescent phases (2 and 4 weeks) after natural infection with H1N1 Pdm in 2009. IgE antibodies developed following the vaccination of young children with seasonal split vaccines, whereas no significant IgE response was observed following natural infection with H1N1 Pdm 2009. The prevalence of IgE antibodies was not influenced by outbreaks of H1N1 Pdm. Repeated immunization with the HA split vaccine induced IgE sensitization against the influenza vaccine irrespective of the H1N1, H3N2, or B influenza subtypes. The reasons why anaphylaxis only occurred in recipients of the influenza vaccine containing 2-phenoxyethanol are still being investigated, and the size distribution of antigen particles may have shifted to a slightly larger size. Since the fundamental reason was IgE sensitization, current split formulation for the seasonal influenza vaccine needs to be reconsidered to prevent the induction of IgE sensitization.

Vaccine allergy

Overdiagnosis of vaccine allergy is considered a major public health problem. This article discusses the different types of allergic reactions after immunization based on the timing (immediate vs nonimmediate) and the extent of the reaction (local vs systemic). The vaccine components potentially responsible for an allergic reaction are discussed, as well as the management of patients with a history of reaction to a specific vaccine and those with a history of allergy to one of the vaccine components.

Immediate hypersensitivity reactions following monovalent 2009 pandemic influenza A (H1N1) vaccines: reports to VAERS

BACKGROUND

Hypersensitivity disorders following vaccinations are a cause for concern.

OBJECTIVE

To determine the type and rate by age, gender, and vaccine received for reported hypersensitivity reactions following monovalent 2009 pandemic influenza A (H1N1) vaccines.

DESIGN

A systematic review of reports to the Vaccine Adverse Event Reporting System (VAERS) following monovalent 2009 pandemic influenza A (H1N1) vaccines.

SETTING/PATIENTS

US Civilian reports following vaccine received from October 1, 2009 through May 31, 2010.

MEASUREMENTS

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.

RESULTS

Of 1984 reports, 1286 were consistent with immediate hypersensitivity disorders and 698 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.

LIMITATIONS

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.

CONCLUSIONS

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.

Assessing the safety of influenza vaccination in specific populations: children and the elderly

Comprehensive monitoring of the safety of influenza vaccines remains a public health priority, particularly as immunization coverage increases across different age groups at the global level. In this review, the authors provide state-of-the-art knowledge on the safety of influenza immunization among children and the elderly. The authors review the safety information in each group separately for inactivated and live attenuated influenza vaccines. Adverse events of special concern including febrile seizure, narcolepsy, asthma and Guillain-Barré syndrome are covered under specific considerations. The authors discuss the current status of the field, particularly the use of new technologies for influenza vaccines and their potential safety profile.

An update on influenza vaccination in patients with egg allergy

PURPOSE OF REVIEW

Egg allergy is a common problem affecting young children especially. There has been much debate over the past several decades on how to approach the subject of influenza vaccination in children with egg allergy.

RECENT FINDINGS

Because of concern regarding the egg protein content in the influenza virus vaccine, pediatricians have in the past typically taken a conservative approach of avoiding influenza vaccination in egg-allergic patients. Subsequently, it was shown that the influenza vaccine could be safely administered to patients who had negative skin testing to the vaccine. Most recently, studies have demonstrated a low risk of giving the vaccine either in divided doses or as a single dose in a controlled setting without the need for skin testing.

SUMMARY

In considering vaccination in a patient with a history of egg allergy, several factors should be weighed, including the severity of the egg allergy, the egg content of vaccines, and the setting of vaccine administration. However, it appears that the risk of anaphylaxis to the influenza vaccine in patients with egg allergy may be much lower than previously thought, suggesting that in many cases skin testing may not be necessary.