Fig. 2.

Effect of storage duration on the vaccines capacity to induce antibody responses. Pooled sera of each group of mice immunized at different time points with liquid or freeze-dried WIV vaccine were tested simultaneously on H5N1-specific IgG or hemagglutination-inhibiting capacity. Bars represent the average values of duplicate determinations (deviations were less than 0.2). Immunization groups are plotted and labeled as in Fig. 1. Storage duration: 0 day (white bars), 3 months (gray bars), 1 year (black bars). nd not determined