Table 1.

Experimental groups

Group	Passive immunization	Days from start of experiment
		1 Prime	10 Boost	35 Challenge
1	PBSa	PBS	No	Viruse
2	PBS	0·5 mld	No	Virus
3	Laboratory antiserumb, neat	0·5 ml	No	Virus
4	Laboratory antiserum, 1:2 dilution	0·5 ml	No	Virus
5	Laboratory antiserum, 1:2 dilution	0·5 ml	Yes	Virus
6	Field antiserumc, neat	0·5 ml	No	Virus
7	Field antiserum, 1:2	0·5 ml	No	Virus
8	Field antiserum, 1:2	0·5 ml	Yes	Virus

^aPhosphate‐buffered saline, negative control for immunization, vaccination, and/or challenge.

^bObtained from birds infected with A/Chicken/Mexico/AvilablA0509/09 (H5N2).

^cObtained from birds vaccinated in the field with A/Chicken/Mexico/AvilablA0509/09 (H5N2).

^dInactivated vaccine prepared against A/Chicken/Mexico/AvilabIA0509/2009 (H5N2).

^eChallenged with A/Chicken/Mexico/AvilablA0509/09 (H5N2).