Table 1.

Model Input Parameters

	Estimate (per condomless sex act)	Range	Distribution	Notes	References
Base Transmission Rate
Male-female transmissibility per condomless sex act	0.0022	0.0010–0.0031	Beta-PERT	Assumes chronic infection	[22–24]
Multiplicative factors
Transmissibility in late stage/advanced HIV infection, characterized by uncontrolled viral replication	1.82	1.29–2.35	Uniform	Only applies if male not on ART	[25, 26]
Male on antiretroviral therapy	0.04	0.01–0.27	Beta-PERT	Assumes male is adherent and suppressed	[27]
Female on preexposure prophylaxis	0.34	0.16–0.72	Beta-PERT	Assumes female is adherent to PrEP	[11]
MTCTa
Probability of MTCT when the female becomes HIV-infected while trying to conceive	0.26	0.18–0.33	Uniform	Only applies if female becomes HIV-infected during attempts at conception and the pregnancy results in a child	[28, 29]
Multiplicative factor applied to MTCT when the female becomes pregnant while trying to conceive and is started on ART at the time of HIV diagnosis and for the duration of her pregnancy	0.33	0.18–0.59	Uniform	Only applies if female becomes HIV-infected during attempts at conception and the pregnancy results in a child	[30–34]

Abbreviations: ART, antiretroviral therapy; HIV, human immunodeficiency virus; MTCT, mother-to-child transmission; PrEP, preexposure prophylaxis.

^a To obtain the probability of MTCT while the mother is on ART, the MTCT probability is multiplied by the multiplicative factor.