TABLE 4.

Public Health Impact and Associated Costs of Varying Assumptions About the Probability of Successful Notification of the Partners of Male Index Patients Younger Than 25 Years, at a Single Genitourinary Medicine Clinic: Great Britain, 1999–2004

	Partnership Type
PN Strategy	Live-In	Regular	Casual	All
Strategy 1
Probability of successful PN, %	0.9	0.5	0.1	NA
Successful PNs likely,a no.	12	25	10	47
Secondary transmissions likely averted,b no.	0	10	9	19
Cost for all successful PNs,c £	292.41	1259.22	1033.79	2585.41
Cost per secondary transmission prevented,d £	∞	125.00	111.11	133.42
Strategy 2
Probability of successful PN, %	0.1	0.5	0.9	NA
Successful PNs likely,a no.	1	25	93	120
Secondary transmissions likely averted,b no.	0	10	84	94
Cost for all successful PNs,c £	32.49	1259.22	9304.08	10 595.78
Cost per secondary transmission prevented,d £	∞	125.00	111.11	112.95
Strategy 3
Probability of successful PN, %	0.5	0.5	0.5	NA
Successful PNs likely,a no.	6	25	52	83
Secondary transmissions likely averted,b no.	0	10	47	57
Cost for all successful PNs,c £	162.45	1259.22	5168.93	6590.60
Cost per secondary transmission prevented,d £	∞	125.00	111.11	116.45

Note. NA = not applicable; PN = partner notification. Strategy 1 assumes that almost all live-in partners are treated; hence, the probability of successful PN is assumed to be 0.9. The probability is assumed to be lower among regular partners (0.5), and lower still (0.1) among casual partners, reflecting the increasing difficulty of successful PN with partners of an increasingly casual nature. Reversing these probabilities, strategy 2 assumes a larger probability of successful PN with casual partners than with regular and live-in partners. Finally, strategy 3 assumes that successful PN is equally probable for all partnership types.

Source. Data from the Second National Survey of Sexual Attitudes and Lifestyles were used with data from the genitourinary medicine clinic to calculate estimates.

^aLikely number of successful PNs with index patients’ partners obtained by multiplying the probability of successful PN by the likely number of partners of each type (shown in Table 2).

^bObtained by multiplying the likely number of successful PNs with index patients’ partners by the absolute risk reduction.

^cCost for all successful PNs with index patients’ partners is assumed to be £25 (US $40) per live-in partnership, £50 (US $80) per regular partnership, and £100 (US $160) per casual partnership. These cost data are hypothetical and are for illustrative purposes only, as clinical services should use their own cost data.

^dObtained by dividing the likely number of secondary transmissions by the cost for all successful PNs with index patients’ partners.