TABLE 4.

Incremental Cost-Effectiveness Ratio ($US/DALY prevented) of Vaccination for Initial Prevention of Clostridium difficile infection (CDI) using the Opportunity Cost of Lost Bed-Days Approach.

Vaccine Efficacy	Clostridium difficile Risk
	0.1%	1.0%	2.5%	5.0%	10.0%	15.0%	20.0%	25.0%
Cost of Vaccination = $25
25%	102,512,396	5,802,049	3,150,365	670,243	219,928	159,819	51,886	9,750
50%	7,835,447	1,774,240	1,120,416	235,026	46,099	Dominant	Dominant	Dominant
75%	9,242,325	1,135,269	437,496	125,266	Dominant	Dominant	Dominant	Dominant
100%	13,588,967	1,114,979	300,389	56,679	Dominant	Dominant	Dominant	Dominant
Cost of Vaccination = $50
25%	355,495,778	9,495,689	4,775,304	1,901,144	697,507	419,099	312,448	189,174
50%	62,561,269	3,928,690	2,619,269	674,142	260,932	130,529	54,358	5,540
75%	38,053,933	3,606,097	1,274,169	448,297	134,118	29,308	Dominant	Dominant
100%	31,053,420	2,377,616	755,625	271,070	46,872	Dominant	Dominant	Dominant
Cost of Vaccination = $100
25%	397,800,954	14,296,136	13,956,184	2,151,773	1,241,526	1,089,628	878,411	949,495
50%	121,217,228	7,336,363	2,797,316	1,645,005	885,973	436,334	277,371	196,372
75%	99,166,559	6,559,099	2,093,538	994,250	421,389	227,919	143,188	68,418
100%	34,978,919	6,098,157	1,590,522	695,307	285,349	147,266	54,144	10,528

NOTE: Dominant = Vaccination is the dominant strategy (i.e., less costly and more effective)