Changing perspective on immunization against influenza.

Current vaccination strategies against influenza rely on decades old technology of strain selection and prolonged labor-intensive, embryonated chicken-egg based production methods. Although, containing both major surface glycoproteins, hemagglutinin (HA) and neuraminidase (NA), the immunity engendered by these vaccines is dominated by the anti-HA response. Consequently, current vaccines are susceptible to failure resulting from significant antigenic drift or shift in the time elapsing from the selection of the vaccine candidate strain and wild-type virus exposure. Therefore, immunity may be of short duration. There must be a change in vaccine strategy to include immunization with both HA and NA to broaden the immune response against influenza. Inclusion of the more slowly evolving NA in a vaccine against influenza will reduce the vulnerability to antigenic changes in a potential emerging influenza virus. Alternative production technologies such as recombinant baculovirus and yeast should be explored to decrease vaccine production times.