Influenza vaccines: a main problem in control of pandemics.

The optimal strategy for control of pandemic influenza is early vaccination with influenza vaccine produced from influenza pandemic strains. However, for pandemic control, vaccine improvements are essential and should include quicker ways of manufacturing and testing of vaccine as well as flexibility on the part of licensing bodies. The production of mass doses of monovalent vaccine in a short time can be more realistic if egg independent production technology can be adopted. In this respect production of an influenza vaccine on a stable cell line can solve many of the problems in increased production of influenza vaccine. But the difficulty with influenza vaccines is that the yield of human influenza viruses on tissue culture is much lower than in embryonated eggs. A new high-yield donor is needed for construction of recombinants with a new pandemic strain, which can replicate in a stable cell line with high titre. The live influenza vaccine may be the most appropriate for prophylaxis of influenza pandemic, as the implementation of this vaccine for mass vaccination is simpler than of inactivated influenza vaccine, and this vaccine, after one immunization of unprime persons, induces local mucocosa immunity which plays an important role in the protection against influenza.