Table 6.

Summary of median HI responses for the 15 sampled farms provided in Table 5 with respect to two thresholds for sero-protection (1:16 and 1:32) and three scenarios of matching between the test antigen and the probable seed strain used in the POL vaccine.

Seed-strain vs. test antigen scenario	Sampling	Number of farms having a median HI titer above the two accepted thresholds for the HI test
		≥1:16	≥1:32
Single standard test antigen (Leg/03) (n = 15 farms)	Pre-POL vaccination	14/15	11/15
	Post-POL vaccination	14/15	14/15
Test antigen matched to the vaccine seed strain (n = 9 farms)	Pre-POL vaccination	7/9	3/9
	Post-POL vaccination	8/9	3/9
Test antigen corresponding to presumed circulating strain at time of study (Kon/07) (n = 15 farms)	Pre-POL vaccination	12/15	11/15
	Post-POL vaccination	14/15	13/15