Table 2.

Survival of BALB/c mice after vaccination and challenge with LD₅₀ of S. Typhimurium SL1344^a

entry	PS–protein vaccineb	mortality at day 28c	survival rate (%)	hazard ratio (95% CI)d	p-valuee	vaccine efficacy (%)f
1	PBS	5/9	44.4	–	–	–
2	7a (BSA)	3/10	70.0	0.435	0.278	56.5
3	7b (OVA)	2/9	77.8	0.395	0.239	60.5
4	7c (FliC)	2/10	80.0	0.259	0.098	74.1
5	8b (FliC)	2/9	77.8	0.395	0.239	60.5
6	9b (FliC)	3/10	70.0	0.378	0.216	62.2

^a Mice were orally challenged with 1 × 10⁶ CFU (LD₅₀) S. Typhimurium SL1344 bacteria

^b The PS − protein conjugates 7a–9b were prepared from unfractionated LFPS of 23 kDa

^c Number of dead mice over total number of test mice

^d Cox proportional hazard model results for the risk of death after challenge of S. Typhimurium SL1344 bacteria. CI is confidence interval

^e Comparison of survival distribution with the PBS group (negative control). The statistics are performed by log-rank test

^f Vaccine efficacy = (1 – hazard ratio) × 100%