Table 3.

Key parameter values for numerical examples of antiretroviral therapy (ART) and prevention for MSM (comprising either preexposure prophylaxis (PrEP) or community-based education (CBE))

Parameter	PrEP and ART	CBE and ART	Source
Time Horizon
Time horizon for program implementation, years, T	20	20	Assumed
Program Constraints
Minimum acceptable ART scale up level, $x_1^{\mathit{\text{min}}}$	50,000	50,000	Assumed
Maximum feasible ART scale up level, $x_1^{\mathit{\text{max}}}$	400,000	400,000	Assumed
Minimum acceptable prevention implementation level, $x_2^{\mathit{\text{min}}}$	10,000	10,000	Assumed
Maximum feasible prevention implementation level, $x_2^{\mathit{\text{max}}}$	3,000,000	3,000,000	Assumed
Health Benefits
Net present QALYs gained per person starting ART, a1	15.53	15.53	Calculated (see Section 3.1)
Net present QALYs gained per person reached by prevention program, a2	1.24	0.222	Calculated (see Section 3.1)
Net present infections averted per person starting ART, b1	0.873	0.873	Calculated47, 51, 53 (see Section 3.1)
Net present infections averted per person reached by prevention program, b2	0.054	0.010	Calculated9, 47, 49, 51, 53 (see Section 3.1)
Net present QALYs gained from receiving ART, qtx	5	5	10
Net present QALYs gained from avoiding infection, qIA	9	9	10, 62
Chance of acquiring HIV in T years, σT	14.6%	14.6%	Calculated47, 51, 52 (see Section 3.1)
ART efficacy in reducing sexual infectivity, εtx	90%	90%	3, 63–65
Prevention efficacy in reducing the chance of HIV acquisition, ε2	44%	8%	9, 49
Costs
Budget for HIV spending, B	$10 billion	$10 billion	Estimated55
Net present cost of starting one person on ART, C1	$118,100	$118,100	Calculated (see Section 3.2)
Net present cost of reaching one person with prevention program for T years, C2	$140,393	$272	Calculated (see Section 3.2)
Net present savings from averting an HIV infection, sIA	$70,000	$70,000	10, 62
Net present lifetime cost of ART for one person, c1	$200,000	$200,000	10
Net present cost of prevention program for one person for T years, c2	$150,000	$2,000	Calculated10, 50 (see Section 3.2)
Overlap constant* for QALYs gained, kQ	1.44E-06	2.62E-07	Calculated (see Appendix)
Overlap constant* for infections averted, kIA	1.51E-07	2.75E-08	Calculated (see Appendix)
Cost of ART above baseline, λ1(x1)	0	0	Assumed
Cost of prevention above baseline, λ2(x2)	.05x2−300 for x2>6,000	.01x2−200 for x2>20,000	Estimated39, 42
Discount rate for costs, QALYs and new infections, r	3%	3%	34

Note: ART = antiretroviral therapy; PrEP = preexposure prophylaxis; CBE = community-based education; QALY = quality-adjusted life year

^*Assumes overlap functions of the form δ_Q(x) = k_Qx₁x₂ and δ_IA(x) = k_IAx₁x₂.