Introduction—Annual vaccination is one of the most efficient and cost-effective strategies to
prevent and control influenza epidemics. Most of currently available influenza vaccines are strong
inducer of antibody responses against viral surface proteins, hemagglutinin (HA) and
neuraminidase (NA), but are poor inducers of cell-mediated immune responses against conserved
internal proteins. Moreover, due to the high variability of viral surface proteins because of
antigenic drift or antigenic shift, many of the currently licensed vaccines confer little or no
protection against drift or shift variants.
Areas covered—Next generation influenza vaccines that can induce humoral immune responses
to receptor-binding epitopes as well as broadly neutralizing conserved epitopes, and cell-mediated
immune responses against highly conserved internal proteins would be effective against variant
viruses as well as a novel pandemic influenza until circulating strain-specific vaccines become
available. Here we discuss vaccine approaches that have potential to provide broad spectrum
protection against influenza viruses.
Expert opinion—Based on current progress in defining cross-protective influenza immunity, it
seems that the development of a universal influenza vaccine is feasible. It would revolutionize the
strategy for influenza pandemic preparedness, and significantly impact the shelf-life and
protection efficacy of seasonal influenza vaccines. |
