Fig. 4. S/P ratio column chart with SD bars per week as determined by ELISA. The error bars show the standard deviation of the means. Group 1, pIRES-F; Group 2, pIRES-HN; Group 3, pIRES-HN/F; Group 4, pIRES-HN+pIRES-F; Group 5, pIRES-F+inactivated vaccine; Group 6, pIRES-HN+inactivated vaccine; Group 7, pIRES-F/HN+inactivated vaccine; Group 8, pIRES-HN+pIRES-F+inactivated vaccine; Group 9, pIRES+ inactivated vaccine; Group 10, inactivated vaccine; Group 11, pIRES.