Influenza A virus vRNA segments contain specific packaging signals at their termini that overlap the coding regions.

These results demonstrated that capsid protein translation from replicating RNA2 is required for specific packaging of the FHV genome.

In addition, we describe recent progress in identifying the specific packaging signals and discuss likely mechanisms by which these RNA elements might operate.

Further improvement could be achieved by producing dose- specific packaging for infants, providing clear instructions and giving the first dose under observation at the HF.