Intranasal Flu Vaccine Appears Safe for Egg-Allergic Kids

Neil Osterweil

February 23, 2015

Children with egg allergy can safely receive intranasal doses of a live attenuated influenza vaccine (LAIV) made with egg protein, say investigators from the United Kingdom and Australia.

In a phase 4 trial, eight of 282 children with egg allergy who received one or two doses of the vaccine had mild, self-limiting symptoms possibly attributable to an allergic reaction, and 26 had lower respiratory tract symptoms within 72 hours of administration. None of the children required medical intervention for the reactions other than routine treatment, however, report Paul J. Turner, PhD, from the Section of Paediatrics (Allergy & Immunology) and Medical Research Council & Asthma UK Centre in Allergic Mechanisms of Asthma, Imperial College London, and the Immunisation, Hepatitis and Blood Safety Department, Public Health England, London, United Kingdom; and the Division of Paediatrics and Child Health, University of Sydney, Australia, and colleagues.

"[T]hese data have demonstrated a safety profile in terms of systemic allergic reactions to LAIV (supplied during the 2013-2014 influenza season) in children with egg allergy, including those with a prior history of anaphylaxis, similar to that previously reported for children without egg allergy. Furthermore, the vaccine appears to be well tolerated in children with a diagnosis of asthma or recurrent wheeze," they write in an article published online February 12 in the Journal of Allergy and Clinical Immunology.

Both inactivated and live attenuated forms of influenza vaccine are cultured in hens' eggs and contain egg proteins that have the potential to spark an allergic or anaphylactic reaction in children with egg allergy.

According to the Centers for Disease Control and Prevention's Advisory Committee on Immunization Practices, LAIV should not be given to persons with egg allergy. The committee's recommendations for the 2014 to 2015 influenza season note that "persons with a history of egg allergy who have experienced only hives after exposure to egg should receive influenza vaccine. Because relatively few data are available for use of LAIV in this setting, [inactivated] or trivalent recombinant influenza vaccine...should be used."

In-Office Administration

Dr Turner and colleagues estimate that there are 60,000 children in the United Kingdom with egg allergy. A blanket injunction against the use of LAIV in this group, they argue, would hamper immunization efforts and raise costs because it would require children with egg allergy to receive injections of inactivated virus in a clinical setting where treatment for acute allergic or anaphylactic reactions are available.

To see whether LAIV could be safely administered in a broader setting, they conducted a study with 282 children from the ages of 2 through 17 years who had been diagnosed with an immunoglobin E–mediated food allergy to egg. Sensitization to egg was confirmed with skin-prick testing.

In all, 115 of the children (41%) had previously had anaphylaxis when exposed to egg, and 67% had a diagnosis of asthma or recurrent wheeze, of whom 51% were using a regular asthma inhaler or other form of prevention.

The children received a total of 433 LAIV doses; some children received only a single dose, primarily because of a lack of available in-date vaccine.

There were 14 adverse events reported in 14 children within 2 hours of vaccine administration. Of these reactions, eight were considered to be a potential immunoglobin E–mediated response, resulting in a potential allergic response rate of 2.8%. The reactions included six episodes of rhinitis, one case of localized urticaria, and one case of mild gastrointestinal discomfort, The reactions were mild and self-limiting, and all occurred within a half-hour of vaccine administration.

The remaining reactions, all but one of which occurred with the first dose of LAIV, included one episode of fever, one mild eczema flare, two nasal obstructions without nasal itch or sneezing, and two cases of transient, nonlocalized, nonspecific skin symptoms. Three of these children had a second dose of vaccine 4 weeks later without incident.

In addition, 26 children (9.4%) had lower respiratory tract symptoms within 72 hours of vaccine administration. Of this group, 13 had wheeze, as reported by parents. None of these children required more than routine medical interventions, the investigators report.

A food-allergy specialist who was not involved in the study told Medscape Medical News that the study's conclusions are sound.

"After looking at this paper, I feel comfortable giving kids with egg allergy, even anaphylaxis, this intranasal influenza vaccine. The article is very convincing, and the study design is very good," said John Leung, MD, director of the Food Allergy Center at Tufts Medical Center and codirector of the Food Allergy Center at the Floating Hospital for Children, both in Boston, Massachusetts.

He noted that the investigators excluded from their study those children who had previously required mechanical ventilation for an anaphylactic reaction to egg, severe unstable asthma, or who had prior allergic reactions to components of the LAIV other than egg.

He added that community-based practitioners who treat children with egg allergy and are concerned about potential adverse reactions can refer the patients to a food allergy center, where they can be monitored for an hour or more after vaccine administration,

"My experience is that majority of private practices don't have the manpower to monitor patients for an hour," he said.

The study was supported by the UK Department of Health Policy Research Programme and by local health authorities. Dr Turner reported receiving research support from the UK Department of Health, the UK Medical Research Council, and the National Institute for Health Research. One coauthor has received support for attendance at scientific meetings from Allergy Therapeutics, ALK-Abello, MEDA Pharmaceuticals, and Thermo Fisher. The other authors and Dr Leung have disclosed no relevant financial relationships.

Allergy Clin Immunol. Published online February 12, 2015. Full text

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