Figure 2.
Probability density function (PDF) of HI titres of a single individual. Gaussian probability distribution of HI titres against the challenge strain of a single individual in low vaccine dose groups. (a) PDF of the HI titres from a single individual in groups where the vaccine and challenge strain have an antigenic distance of 0 (i.e. homologous groups H5N1 R65 vaccinated/H5N1 R65 challenged and H5N1 t/T vaccinated/H5N1 t/T challenged). (b) PDF of the HI titres from a single individual in a group where the distance between the vaccine and the challenge strain is 80.88 (26.34) HIU (i.e. H5N2 vaccinated/H5N1 R65 challenged). The blue vertical line crosses at HI = 8 units (threshold value calculated by the analysis).