Cross-protection against drifted influenza viruses

Abstract

Antigenic drift, the evolutionary mechanism of influenza viruses, results in an increased susceptibility of vaccinated subjects against circulating viruses. New vaccines able to grant a broader and cross-reactive immune response against drifted influenza variants are needed. Several strategies were explored to enhance the immunogenicity of plain vaccines: adjuvants, carriers and intradermal administration of influenza vaccine emerge as a promising options. To evaluate the ability of a MF59™-adjuvanted and intradermal influenza vaccine to elicit an effective antibody response against circulating viruses presenting antigenic patterns different from those of the vaccine strains, we compared antibody responses elicited by “implemented” vaccines and conventional intramuscular trivalent inactivated vaccine against heterologous circulating influenza A viruses. Different studies, simulating different epidemiological pictures produced by the natural antigenic drift of seasonal influenza viruses, highlighted the superior cross-reactivity of the antibodies elicited by MF59™ and intradermal vaccines, compared with subunit or split vaccine against heterologous viruses.

Keywords: :

• MF59™
• adjuvants
• antigenic drift
• cross-protection
• influenza vaccine
• intradermal

Disclosure of Potential Conflicts of Interest

F.A., G.I. and P.D. have previously participated at speaker’s bureaus and advisory board meetings sponsored by GSK, Novartis, Pfizer and Sanofi Pasteur and have received research funding as principal investigators or co-investigators from Crucell Berna, Novartis, GSK, Pfizer and Sanofi Pasteur. A.O., D.D.F., A.C., V.P., P.C. and M.C. have no conflict of interest. No other relationships/conditions/circumstances that present a potential conflict of interest exist.