ABSTRACT
Recent findings indicate that seasonal influenza vaccination or infection of healthy humans may contribute to heterosubtypic immunity against new influenza A subtypes, such as H5N1. Here, we investigated whether seasonal influenza vaccination in a mouse model could induce any immunity against the H5N1 subtype. It could be demonstrated that, largely due to the H1N1 component strain A/NewCaledonia/20/99, parenteral immunization of mice with a trivalent seasonal influenza vaccine elicited heterosubtype H5-reactive antibodies able to confer partial protection against H5N1 influenza virus infection. Furthermore, the trivalent seasonal influenza vaccine was found to be compatible with a whole virus H5N1 vaccine in a heterologous prime-boost immunization regimen, achieving superior efficacy compared to a single immunization with an equivalent low-dose of the H5N1 vaccine.
