Figure 1.Antibody TitersTiters of H1N1-specific antibodies in individual sera are shown in (a) for aged and in (d) for younger subjects, titers of H3N2-specific antibodies in individual sera are shown in (b) for aged and in (e) for younger subjects. c shows mean titers of H1N1 (closed circles) and H3N2 (open circles in the aged); f shows mean titers in the younger individuals using the same symbols.
