Guidelines for measles vaccination in egg-allergic children

[MMR vaccine and egg allergy. Experience in a hospital immunization unit]

INTRODUCTION

We review the scientific evidence on the safety of the measles, mumps, and rubella (MMR) vaccine (produced in chicken embryo cell culture) in children with egg allergy. Data on the reactogenicity observed with this vaccine in a large series of children with this type of allergy immunized in an hospital immunization unit are presented.

MATERIAL AND METHODS

An observational prospective study was performed in the International Immunization Unit of the Epidemiology and Preventive Medicine Service of the Vall d'Hebron University Hospital from March 2004 to December 2005. Demographic variables, clinical history of allergy, and the adverse reactions observed 30 minutes after vaccine administration were analyzed.

RESULT

A total of 140 patients (106 referred for the first MMR vaccine dose, and 34 for the second) were evaluated. Of these, 75.7 % showed clinical signs after egg ingestion (severe reactions were described in only seven patients: respiratory distress in six and systemic anaphylaxis in one). The MMR vaccine was administered to 121 children. No significant adverse reactions were observed (17.8 % of the vaccinated children developed mild local symptoms).

CONCLUSIONS

According to current scientific evidence and the data obtained in this study, the MMR vaccine is safe in patients with egg allergy.

Recommendations for administering the triple viral vaccine and antiinfluenza vaccine in patients with egg allergy

Actually, food allergy is an emerging pathology; and egg allergy is the most frequent in childhood. The recommendations for measles, mumps and rubella (MMR) and influenza vaccination are increasing each year. This implementation increases the exposure of patients with egg allergy to such vaccines. In Spain, since 2004 the only available vaccine for MMR is grown in cultures of fibroblast from chick embryos; previously, patients with egg allergy were vaccinated with an alternative vaccine cultivated in diploid human cells which is no longer commercialized. Influenza vaccines grow in chick egg and the final product contains egg proteins (large variation in egg protein content has been reported). As controversy exist, the Food Allergy Committee of Spanish Society of Clinical Immunology and Pediatric Allergy decided to report some recommendations for the safe administration of MMR and influenza vaccines in patients with egg allergy. In summary, MMR vaccine is safe for children with egg allergy, only in patients with severe anaphylactic reaction after egg ingestion is recommended the administration in his reference hospital. Influenza vaccine is contraindicated in patients with severe anaphylactic reaction after egg ingestion. The rest can receive influenza vaccine in a 2-dose protocol with a vaccine that contains no more than 1.2 mcg of egg protein for mL.

The complex link between immunization against childhood diseases and allergy

Vaccines can be at the origin of allergic manifestations in susceptible children. Such manifestations include: immediate-type hypersensitivity (anaphylactic shock, rash or angioedema) within 1 h after the injection; semi-late hypersensitivity (local inflammatory lesion such as the Arthus phenomenon) a few hours after the injection; and delayed-type hypersensitivity (abscess or eczema at the site of the injection). Furthermore, early-life vaccinations have been implicated in the modulation of the immune system as they could promote the development of allergy by avoiding infections. However, most population-based studies have not found an increased risk of allergies in vaccinated children. Due to methodological problems in conducting the studies, further investigations are needed to better understand the phenomenon.

Seguridad de la vacunación triple vírica en pacientes con alergia al huevo

In Spain, for many years allergy to eggs was considered to contraindicate vaccines cultured in fibroblasts from chick embryos such as the measles, mumps, rubella (MMR) and influenza vaccines. Consequently, an alternative vaccine (Triviraten Berna) incubated in diploid human cells has been systematically administered to children who are allergic to eggs, without questioning tolerance to the standard MMR vaccine. After Biotech Bern Laboratory discontinued the production of Triviraten, this alternative was no longer available for children with egg allergy, who should receive a first dose of the MMR vaccine at the age of 15 months and a second one (booster dose) at the age of 3 years. In this context, from November 2004 to June 2005, a single dose of the MMR vaccine was administered to 40 children with allergy to eggs and none showed an adverse reaction. We conclude that this vaccine can be safely administered to this group of patients.

Vaccine allergy: diagnosis and management

As a group, vaccines provide a safe and effective way of preventing infectious and allergic illness. Allergic reactions to vaccines and drug products have become important and common features of practice and demand heightened awareness. Serious adverse effects of vaccines are rare but have been reported to various components of different vaccines. Although there are few precise diagnostic tests available, patients usually can be diagnosed accurately after careful attention to the history and physical findings. Better understanding of these reactions can lead to proper vaccine selection and can improve immunization acceptance rates in the community. Prevention, avoidance, use of alternative agents, desensitization, and premedication remain the mainstays of therapy, even as more refined diagnostic and management tools are developed. VAERS data, in addition to the traditional uses (signal detection, large registry of rare vaccine adverse events), can serve as a source of cases for epidemiologic (eg, case-control) studies that evaluate biologic factors that may be related to vaccine-related adverse reactions. Additional studies that are aimed at identifying other causes of immediate hypersensitivity after immunization with live virus vaccines are warranted.