Figure 3.

 The un‐rooted consensus phylogenetic tree expressing the relationship between the HA1 amino acid sequences of the Kenyan 2006–2007 isolates to southern hemisphere vaccine strains used from 1999 to 2008 and South African isolates (2004–2006). The tree was produced using Neighbor Joining (NJ) method generated by mega 3.1 software. ¹⁵ The phylogeny test was done by Bootstrap based on 500 replications. The accession numbers corresponding to the protein sequences are given by the gi numbers. The year for each southern hemisphere vaccine strain is indicated on the branches.