DNA vaccination of ferrets with chimeric influenza A virus hemagglutinin (H3) genes.

Recently a technology was established based on homologous recombination that allowed the rapid generation of chimeric HA genes of influenza viruses, containing the antigenic determinants obtained from various influenza virus A (H3N2) viruses. In the present report plasmids were generated using a H3 HA vector handle and the hypervariable regions of two genetically distinct influenza A H3N2 viruses, A/Stockholm/7/97 and A/Netherlands/18/94. In a ferret model it was shown that immunisation with plasmid DNA encoding chimeric HA indeed elicited antibody responses specific for the virus from which the hypervariable region with the antigenic determinants were obtained.

The humoral response to live and inactivated influenza vaccines administered alone and in combination to young adults and elderly.

Background: Vaccination is the most effective way for prevention of severe influenza infection, but the present vaccines are not very efficient in the elderly.

Objective: In this study, we investigated the Ig isotype response to a cold adapted, live, attenuated influenza vaccine (LIV) and a trivalent, subunit, inactivated influenza vaccine (IIV) and the combination of both (LIV/IIV) in young and elderly men, not previously vaccinated against influenza.

Study Design: LIV and IIV containing the strains for 1998-1999 were used.