The FDA recently approved FluBlok, a new influenza vaccine that is based on hemagglutinin (one of surface proteins on the influenza virus that is strain-specific) and is made using recombinant protein technology rather than using chicken eggs. As a result of the manufacturing process, this new vaccine contains no egg protein, thimerosal or other preservatives. This may represent an advantage for patients with egg allergy or concern for thimerosal. However, numerous recent studies show that the traditional influenza vaccine is safe for people even with severe egg allergy (although certain precautions should be taken -- see your doctor for details).
FluBlok is a seasonal influenza vaccine, and is based on the most common strains of influenza expected during the flu season. However, the company claims that because the vaccine is based on pure hemagglutinin protein, protection against the flu may be better than with the traditional vaccine, even with different strains of influenza. At the present time, FluBlok is only indicated for patients 18-49 years of age, and is available only in limited amounts this year.