Table 5.

Virus titers in nasal swabs from pigs with maternally-derived antibodies (MDA) from exposed sows vaccinated with H1N1pdm09 whole inactivated virus (WIV-MDA) vaccine or experimentally infected with H1N1pdm09 (EXP-MDA), or from a non-boosted H1N1pdm09 naturally exposed sow (NAT-MDA), and without MDA (No MDA) at 1 to 5 days post infection (dpi) with homologous H1N1pdm09(2:6) or heterologous H1N2-δ1(1:7) in Study 2. Values shown as mean ± standard error of the mean (SEM).

Challenge Groups	Nasal swabsx					BALFx
	1 dpi	2 dpi	3 dpi	4 dpi	5 dpi	5 dpi
No MDA/NC	0.0 ± 0.0a	0.0 ± 0.0a	0.0 ± 0.0a	0.0 ± 0.0a	0.0 ± 0.0a	0.0 ± 0.0a
Homologous
No MDA/H1N1	1.2 ± 0.3b	1.1 ± 0.2b	1.7 ± 0.2b	2.3 ± 0.2b	1.0 ± 0.2b	4.2 ± 0.3b
WIV-MDA/H1N1	0.0 ± 0.0a	0.1 ± 0.1a	0.0 ± 0.0a	0.1 ± 0.1a	0.1 ± 0.1a	0.0 ± 0.0a
EXP-MDA/H1N1	0.0 ± 0.0a	0.6 ± 0.3a,b	0.6 ± 0.4a	0.7 ± 0.3a	0.4 ± 0.1a,b	3.7 ± 0.6b
Heterologous
No MDA/H1N2	2.8 ± 0.3b	2.6 ± 0.2b	3.3 ± 0.3b	3.1 ± 0.2b	3.0 ± 0.2b	5.1 ± 0.3b
WIV-MDA/H1N2	2.5 ± 0.6b	2.1 ± 0.4b	3.0 ± 0.3b	2.9 ± 0.2b	1.6 ± 0.4c	6.0 ± 0.2b,c
EXP-MDA/H1N2	2.8 ± 0.4b	2.6 ± 0.5b	3.0 ± 0.2b	2.7 ± 0.3b	2.8 ± 0.4b	6.8 ± 0.2c
NAT-MDA /H1N2	1.1 ± 0.5c	3.1 ± 0.4b	2.3 ± 0.4b	2.8 ± 0.1b	2.5 ± 0.4b,c	6.1 ± 0.2b,c

^xVirus titers represented as log₁₀ TCID₅₀/ml.

^a,b,cStatistically significant differences identified with different lowercase letters (P ≤ 0.05).