Rather than being cultured in eggs, Flucelvax is cultured in mammalian cells and Flublock is grown in caterpillar cells injected by an insect virus containing the flu gene.
Both vaccines are approved for use in people 18 years and older.
Why the concern of egg-allergic patients with the traditional flu vaccine used to defend against both seasonal and pandemic flu virus?
Traditionally, the flu shot vaccine (both H1N1 and seasonal) are grown inside eggs which is where this concern arises. It also doesn't help that the pre-flu shot questionnaire specifically asks about egg allergy. Though egg-based, during vaccine production the egg protein is filtered out such that there should be no egg contaminants in the final vaccine. However, it is theoretically possible that some egg may still be present in the vaccine.
Although there is an infinitesimal possibility of egg contaminants, studies have shown that even patients with life-threatening egg allergy can still safely have the flu vaccine.
In spite of these reassurances, there are still concerns from patients and healthcare professionals which makes the availability of two different egg-free flu vaccines welcome news.
Source:
FDA approves next-generation, bug-based flu vaccine. MSNBC 1/16/13
