Table 2.

Studies assessing effects of antiretroviral treatment on HIV transmission.

Author	Study location	No. of couples	Study population	Conclusions
Retrospective cohorts
Musicco et al. [34]	Italy	436	HIV + clinic and HIV surveillance center clients and their seronegative partners	ART in HIV-infected men reduces, but does not eliminate, heterosexual transmission of infection
Castilla et al. [28]	Spain	393	HIV clinic patients and their seronegative partners	Combined ART applied according to current guidelines has a great potential for preventing HIV transmission to sexual partners
Prospective cohorts
Bunnell et al. [31]	Uganda	926	ART-naive HIV-positive adults enrolled in home-based ART program reporting on their partners (stable/nonstable, HIV-positive/negative)	ART, prevention counseling, and partner VCT associated with reduced estimated risk of HIV transmission during first 6 months of therapy
Del Romero et al. [29]	Spain	424	Couples recruited through HIV-positive patients at an HIV/STI clinic	Heterosexual infectivity of HIV in individuals taking effective antiretroviral treatment is low
Donnell et al. [30]	Botswana, Kenya, Rwanda, South Africa, Tanzania, Uganda, Zambia	3381	HIV-positive and HSV-positive individuals and their HIV-negative partners from the partners in prevention HSV/HIV Transmission Study	Provision of ART to HIV-infected patients could be an effective strategy to achieve population-level reductions in HIV transmission
Hernando et al. [32]	Spain	339	HIV-positive patients and their partners attending a HIV/STI clinic	Couples-based safe sex counseling and ART can reduce but not eliminate sexual HIV transmission
Melo et al. [33]	Brazil	93	HIV clinic patients and their seronegative partners	Transmitters showed significantly higher median viral loads, suggesting that heterosexual transmission of HIV is more a function of viral load than sex of index case. Antiretroviral use may play a role in the prevention of HIV heterosexual transmission
Reynolds et al. [35]	Uganda	250	Serodiscordant couples offered free ART if eligible	HIV transmission may be reduced among HIV-discordant couples after initiation of ART due to reductions in viral load and increased consistent condom use
Sullivan et al. [36]	Rwanda, Zambia	2993	Serodiscordant couples initiated on ART if eligible	ART was associated with a 94% reduction in transmission; ART initiation is a critical component of a package of biomedical and behavioral prevention services
Wang et al. [37]	China	1927	Former plasma donors and their seronegative spouses	Transmission events occurred with equal frequency in couples regardless of whether the partner was provided ART

ART, antiretroviral therapy; HSV, herpes simplex virus; STI, sexually transmitted infections; VCT, voluntary counseling and testing.