Fig 3.

Influenza vaccine-specific serum IgG levels. Piglets were vaccinated on day 7 and day 14 with a 0.25-ml i.m. injection of human influenza vaccine. A prevaccination blood sample was drawn on day 7, and blood samples were collected longitudinally from all piglets on day 14 and day 21. On day 14 and day 21, vaccinated piglets had greater serum influenza vaccine-specific IgG than nonvaccinated piglets (P < 0.0001). Vaccinated piglets had greater serum influenza vaccine-specific IgG levels at day 21 than at day 14 (P < 0.0001). Values are expressed as means ± SD. Repeated-measures ANOVA: overall model, P = 0.02; diet, P = 0.17; day, P < 0.001; and diet-day interaction, P = 0.68.