1 Cohen MS

Chen YQ

McCauley M

et al. Prevention of HIV-1 infection with early antiretroviral therapy. 2 Cohen J Breakthrough of the year. HIV treatment as prevention. 1 Cohen MS

Chen YQ

McCauley M

et al. Prevention of HIV-1 infection with early antiretroviral therapy. 3 Baggaley RF

White RG

Boily MC HIV transmission risk through anal intercourse: systematic review, meta-analysis and implications for HIV prevention. 4 Rodger AJ

Cambiano V

Bruun T

et al. Sexual activity without condoms and risk of HIV transmission in serodifferent couples when the HIV-positive partner is using suppressive antiretroviral therapy. , 5 Rodger AJ

Cambiano V

Bruun T

et al. Risk of HIV transmission through condomless sex in serodifferent gay couples with the HIV-positive partner taking suppressive antiretroviral therapy (PARTNER2): final results of a multicentre, prospective, observational study. In December, 2011, Science recognised the findings of the HPTN 052 studyas the scientific breakthrough of the year.This study showed a 96% reduction in sexual transmission of HIV in serodifferent couples (one partner HIV positive, the other HIV negative) when the HIV-positive partner was successfully treated with antiretroviral therapy (ART).However, the HPTN 052 study included only a small number of men who have sex with men (MSM), for whom HIV acquisition often includes anal exposure, an efficient route of HIV transmission.Furthermore, the couples in the HPTN 052 study were counselled to use condoms, so the observed benefits of ART also reflected the contribution of safer sexual behaviours. Accordingly, other investigatorshave subsequently studied HIV transmission in couples who specifically chose not to use condoms.

4 Rodger AJ

Cambiano V

Bruun T

et al. Sexual activity without condoms and risk of HIV transmission in serodifferent couples when the HIV-positive partner is using suppressive antiretroviral therapy. 5 Rodger AJ

Cambiano V

Bruun T

et al. Risk of HIV transmission through condomless sex in serodifferent gay couples with the HIV-positive partner taking suppressive antiretroviral therapy (PARTNER2): final results of a multicentre, prospective, observational study. In 2016, the results of the PARTNER study were reported,a study that had enrolled 1166 serodifferent couples at 75 sites in 14 European countries between 2010 and 2014; 340 gay couples were included. The study reported no HIV transmission from ART-treated gay men with viral suppression to their sexual partners, but the upper confidence limit of calculated risk from unprotected receptive anal intercourse with ejaculation was 2·70 per 100 couple-years of follow-up. The estimate for HIV transmission in gay couples was less precise than that obtained for heterosexual couples because of the lower number of couple-years of follow-up accrued; thus, the investigators launched the PARTNER2 study, the results of which are now reported by Alison Rodger and colleaguesin The Lancet. From 2014 to 2017, the investigators continued recruitment of an additional 495 gay couples. In the PARTNER2 study, 782 couples provided evaluable results over 1593 couple-years of follow-up, including 76 088 self-reported episodes of condomless anal intercourse. The investigators observed no episodes of HIV transmission from the HIV-positive partners to their HIV-negative sexual partners. They concluded that the risk of HIV transmission from an HIV-infected man receiving ART with a plasma HIV-1 RNA (viral load) of less than 200 copies per mL over the preceding year was, remarkably, zero, with a narrow upper 95% CI limit of 0·23 per 100 couple-years of follow-up.

6 Antiretroviral Therapy Cohort Collaboration

Survival of HIV-positive patients starting antiretroviral therapy between 1996 and 2013: a collaborative analysis of cohort studies. 1 Cohen MS

Chen YQ

McCauley M

et al. Prevention of HIV-1 infection with early antiretroviral therapy. , 4 Rodger AJ

Cambiano V

Bruun T

et al. Sexual activity without condoms and risk of HIV transmission in serodifferent couples when the HIV-positive partner is using suppressive antiretroviral therapy. , 5 Rodger AJ

Cambiano V

Bruun T

et al. Risk of HIV transmission through condomless sex in serodifferent gay couples with the HIV-positive partner taking suppressive antiretroviral therapy (PARTNER2): final results of a multicentre, prospective, observational study. , 7 Bavinton BR

Pinto AN

Phanuphak N

et al. Viral suppression and HIV transmission in serodiscordant male couples: an international, prospective, observational, cohort study. 8 Pilcher CD

Tien HC

Eron Jr, JJ

et al. Brief but efficient: acute HIV infection and the sexual transmission of HIV. 9 Ratmann O

van Sighem A

Bezemer D

et al. Sources of HIV infection among men having sex with men and implications for prevention. These important results serve to inspire and challenge us. Timely identification of HIV-infected people and provision of effective treatment lead to near normal health and lifespanand virtual elimination of the risk of HIV transmission.Yet maximising the benefits of ART has proven daunting, especially for MSM. It is not always easy for people to get tested for HIV or find access to care; in addition, fear, stigma, homophobia, and other adverse social forces continue to compromise HIV treatment. Furthermore, diagnosis of HIV infection is difficult in the early stages of infection when transmission is very efficient,and this limitation also compromises the treatment as prevention strategy.

10 Fauci AS

Redfield RR

Sigounas G

Weahkee MD

Giroir BP Ending the HIV epidemic: a plan for the United States. 5 Rodger AJ

Cambiano V

Bruun T

et al. Risk of HIV transmission through condomless sex in serodifferent gay couples with the HIV-positive partner taking suppressive antiretroviral therapy (PARTNER2): final results of a multicentre, prospective, observational study. 8 Pilcher CD

Tien HC

Eron Jr, JJ

et al. Brief but efficient: acute HIV infection and the sexual transmission of HIV. , 9 Ratmann O

van Sighem A

Bezemer D

et al. Sources of HIV infection among men having sex with men and implications for prevention. The US Government has recently announced a plan to end the HIV epidemic in the USA in the next 10 years.The pillars of the strategic initiative include detection and treatment of HIV without delay, a goal clearly justified by the PARTNER2 results.The plan also includes detection and accelerated treatment of clusters of HIV-infected people with related HIV variants and social linkage; such clusters are often driven by the presence of undetected acute and early infections.

4 Rodger AJ

Cambiano V

Bruun T

et al. Sexual activity without condoms and risk of HIV transmission in serodifferent couples when the HIV-positive partner is using suppressive antiretroviral therapy. , 5 Rodger AJ

Cambiano V

Bruun T

et al. Risk of HIV transmission through condomless sex in serodifferent gay couples with the HIV-positive partner taking suppressive antiretroviral therapy (PARTNER2): final results of a multicentre, prospective, observational study. 7 Bavinton BR

Pinto AN

Phanuphak N

et al. Viral suppression and HIV transmission in serodiscordant male couples: an international, prospective, observational, cohort study. , 9 Ratmann O

van Sighem A

Bezemer D

et al. Sources of HIV infection among men having sex with men and implications for prevention. 1 Cohen MS

Chen YQ

McCauley M

et al. Prevention of HIV-1 infection with early antiretroviral therapy. 1 Cohen MS

Chen YQ

McCauley M

et al. Prevention of HIV-1 infection with early antiretroviral therapy. , 4 Rodger AJ

Cambiano V

Bruun T

et al. Sexual activity without condoms and risk of HIV transmission in serodifferent couples when the HIV-positive partner is using suppressive antiretroviral therapy. , 5 Rodger AJ

Cambiano V

Bruun T

et al. Risk of HIV transmission through condomless sex in serodifferent gay couples with the HIV-positive partner taking suppressive antiretroviral therapy (PARTNER2): final results of a multicentre, prospective, observational study. , 7 Bavinton BR

Pinto AN

Phanuphak N

et al. Viral suppression and HIV transmission in serodiscordant male couples: an international, prospective, observational, cohort study. 5 Rodger AJ

Cambiano V

Bruun T

et al. Risk of HIV transmission through condomless sex in serodifferent gay couples with the HIV-positive partner taking suppressive antiretroviral therapy (PARTNER2): final results of a multicentre, prospective, observational study. Results of the PARTNER studiesalong with those from other studies of MSMand heterosexual couplesalso emphasise the impact of additional sexual relationships outside the couples. Incident sexually transmitted infections have frequently been detected in either partner in studies of serodifferent couples, indicating additional sexual contacts.In gay couples in the PARTNER studies, a total of 15 HIV infections acquired outside the primary partnership were observed.

Copyright © 2019 Ajit Solanki/Associated Press

4 Rodger AJ

Cambiano V

Bruun T

et al. Sexual activity without condoms and risk of HIV transmission in serodifferent couples when the HIV-positive partner is using suppressive antiretroviral therapy. , 5 Rodger AJ

Cambiano V

Bruun T

et al. Risk of HIV transmission through condomless sex in serodifferent gay couples with the HIV-positive partner taking suppressive antiretroviral therapy (PARTNER2): final results of a multicentre, prospective, observational study. 11 Centers for Disease Control and Prevention

Preexposure prophylaxis for the prevention of HIV infection in the United States–2017 update: a clinical practice guideline. 10 Fauci AS

Redfield RR

Sigounas G

Weahkee MD

Giroir BP Ending the HIV epidemic: a plan for the United States. 10 Fauci AS

Redfield RR

Sigounas G

Weahkee MD

Giroir BP Ending the HIV epidemic: a plan for the United States. , 11 Centers for Disease Control and Prevention

Preexposure prophylaxis for the prevention of HIV infection in the United States–2017 update: a clinical practice guideline. 12 Siegel K

Meunier E Awareness and perceived effectiveness of HIV treatment as prevention among men who have sex with men in New York City. Use of pre-exposure prophylaxis (PrEP) with the combination of emtricitabine and tenofovir disoproxil fumarate by the HIV-negative partner was an exclusion criterion for eligible couple-years of follow-up in the PARTNER studies,but this intervention has emerged as an important method for HIV preventionand is one of the pillars of the US HIV elimination plan.PrEP offers protection from HIV acquisition.Indeed, a recent survey reported PrEP to be more popular and trusted by MSM for HIV prevention than treatment as prevention,reflecting the complex considerations of the HIV-negative partner in a sexual relationship.

10 Fauci AS

Redfield RR

Sigounas G

Weahkee MD

Giroir BP Ending the HIV epidemic: a plan for the United States. It has taken considerable time and massive effort to prove that antiretroviral drugs can prevent HIV through treatment or as PrEP. During the course of these studies, antiretroviral drugs have become more effective, reliable, durable, easier to take, well tolerated, and much less expensive. The results of the PARTNER2 study provide yet one more catalyst for a universal test-and-treat strategy to provide the full benefits of antiretroviral drugs. This and other strategiescontinue to push us toward the end of AIDS.

I report advisory board travel fees from Merck and Gilead, outside the area of work commented on here.