| abstract |
The present invention relates to a reassortant influenza A virus comprising an altered H3 HA protein that is replication enhanced in embryonated chicken eggs relative to the virus without the altered H3 HA protein, wherein the altered H3 HA protein comprises substitutions at positions 186 and 196; wherein the substitutions change the amino acids at positions 186 and 196 to valine and threonine, respectively. |