Influenza vaccination of the egg-allergic individual

To the Editor: Australian influenza notification and hospitalisation rates are highest in children aged under 5 years,1 the group most commonly affected by egg allergy (estimated to affect 8.9% of infants aged 12 months in a recent Melbourne study).2 The ability to safely vaccinate egg-allergic individuals is thus an important public health issue, particularly in the context of potentially pandemic influenza. More than 98% of over 4000 egg-allergic individuals have tolerated vaccination under direct medical supervision in published studies.3-6 As a result, Australian and several international guidelines3,5,6 recommend that influenza vaccination of the egg-allergic individual may be undertaken using a two-step protocol (10%–90% vaccine dose, 30 minutes apart with a final 30-minute waiting period), as long as vaccines contain less than 1 μg egg ovalbumin/dose. Prior allergy testing with the vaccine is not recommended. All currently available influenza vaccines for the 2011 season in Australia have less than 1 μg ovalbumin/dose, specifically Influvac (Abbott Pharmaceuticals, < 1 μg/dose), Intanza (Sanofi Pasteur, < 0.05 μg), Vaxigrip and Vaxigrip Junior (Sanofi Pasteur, < 0.05 and < 0.025 μg, respectively), Fluvax (CSL, < 1 μg), Agrippal (Novartis, < 0.20 μg) and Fluarix (GlaxoSmithKline Australia, < 0.05 μg). Based on current evidence, we suggest that the 2011 seasonal influenza trivalent vaccines can be safely administered in a medically supervised primary care setting as a single dose with a 30-minute observation period (rather than the standard 15 minutes) in those with non-anaphylactic reactions to egg. In those with a history of egg anaphylaxis (or positive allergy tests without a history of ingestion), we recommend a split-dose protocol after discussion with an allergy specialist. We acknowledge that these guidelines are at variance with those in the Australian immunisation handbook,7 but they are consistent with more recent evidence and international recommendations. Whether it is also safe to administer vaccines containing more than 1 μg ovalbumin/dose8 awaits confirmation in a larger patient population and is not currently recommended.