Safety of Nasal Influenza Immunisation in Egg Allergic Children - The SNIFFLE 2 Study

Phase 4 Study to Assess the Safety of Nasal Influenza Immunisation in Egg Allergic Children - a Multicentre Observational Study

Egg allergy is common in early childhood, affecting at least one in 50 preschool children. Influenza ("'flu") vaccines contain egg protein, as the vaccine is cultured in hen's eggs. There is robust data to support the safety of influenza vaccines (containing low or negligible amounts of egg protein) in patients with egg allergy.

A new influenza vaccine, known as LAIV (Live Attenuated Intranasal Vaccine) has recently been approved by a number of licensing boards and is given by a spray into the nose. This new vaccine has been available in the United States for several years and is highly effective and against influenza infection, with an excellent safety profile in children without egg allergy. However, LAIV is also grown in hen's eggs and contains egg protein, and there are NO published data on the safety of LAIV in egg-allergic children. In SNIFFLE 1 Study, 433 doses were given to 282 egg-allergic children; data is currently being analysed.

The objective of this multicentre study is to further assess the safety of intranasal LAIV in egg-allergic children, in order to demonstrate that these children can safely be given the new LAIV within a primary care health environment.

Inclusion Criteria:

• Aged 2 - 17 years old
• Physician-diagnosis of egg allergy

Exclusion Criteria:

1. Clinical resolution of egg allergy

2. Contraindications to LAIV (notwithstanding allergy to egg protein):

   • Hypersensitivity to the active ingredients, gelatin or gentamicin (a possible trace residue)
   • Previous systemic allergic reaction to LAIV
   • Previous allergic reaction to an influenza vaccine (not LAIV) is a relative contra-indication, which must be discussed with the site PI to confirm patient suitability
   • Children/adolescents who are clinically immunodeficient due to conditions or immunosuppressive therapy such as: acute and chronic leukaemias; lymphoma; symptomatic HIV infection; cellular immune deficiencies; and high-dose corticosteroids. NB: LAIV is not contraindicated for use in individuals with asymptomatic HIV infection; or individuals who are receiving topical/inhaled corticosteroids or low-dose systemic corticosteroids or those receiving corticosteroids as replacement therapy, e.g. for adrenal insufficiency.
   • Children and adolescents younger than 18 years of age receiving salicylate therapy because of the association of Reye's syndrome with salicylates and wild-type influenza infection.

3. Contraindication to vaccination on that occasion, due to child being acutely unwell:

   • Febrile ≥38.0oC in last 72 hours
   • Acute wheeze in last 72 hours requiring treatment beyond that normally prescribed for regular use by the child's treating healthcare professional
   • Recent admission to hospital in last 2 weeks for acute asthma
   • Current oral steroid for asthma exacerbation or course completed within last 2 weeks