Evidence-Based Answers

Evidence Central™ is an integrated web and mobile solution that helps clinicians quickly answer etiology, diagnosis, treatment, and prognosis questions using the latest evidence-based research.


Evidence Central for Mobile Devices

Evidence Central iOS iPhone iPad Android

Evidence Central from Unbound Medicine, available for iOS® and Android™, is optimized for each platform and features superior navigation, so answers are easy to find at the bedside or anywhere they’re needed. Learn More

Word of the Day

Early antiretrovirals prevent HIV transmission to partners

Clinical Question:
Does early initiation of antiretrovirals in patients with HIV reduce the risk of transmission to their sexual partners?

Bottom Line:
Early initiation of antiretroviral therapy (when the CD4 count is between 350 and 550 cells/mL3) reduces the risk of transmission to uninfected partners (number needed to treat [NNT] = 62). (LOE = 1b)

Cohen MS, Chen YQ, McCauley M, et al, for the HPTN 052 Study Team. Prevention of HIV-1 infection with early antiretroviral therapy. N Engl J Med 2011;365(6):493-505.  [PMID:21767103]

Study Design:
Randomized controlled trial (nonblinded)




Early initiation of antiretroviral therapy, defined as initiation when the CD4 count is between 350 and 550 cells/mL3, may be of benefit to the patient, though prospective randomized trials are lacking. In this study, early initiation was compared with late initiation (waiting till the CD4 count was < 250 cells/mL3) to assess the effect on transmission of HIV to sexual partners. A total of 1763 HIV discordant couples who were in a monogamous relationship for at least 3 months were randomized to receive early or late initiation. CD4 counts were monitored, as was HIV status of the noninfected member of the couple. If a couple split up, a new partner could be added to the study as long as they were HIV negative. Almost all of the couples were heterosexual, 94% were married, and approximately 5% had unprotected sex at least once during the previous week. Patients were recruited at 13 sites in Africa, South America, India, Thailand, and the United States. Groups were balanced, with most patients falling between the ages of 26 years and 40 years, and most having primary or secondary schooling. Median follow-up of the study was 1.7 years. Follow-up was between 86% and 93% at the semi-annual visits. The primary outcome was HIV infection in the previously uninfected partner, which occurred much less frequently in the early intervention group (0.3/100 person years vs 2.2/100 person years; P < .001). The NNT to prevent 1 transmission was 53 for all transmissions. In some cases the infection was not virologically linked to the partner, perhaps because the uninfected partner had sex outside of their relationship. When considering only transmissions that were virologically linked to the partner, the incidence rates were 0.1 versus 1.7 per 100 person-years, for an NNT of 62. The composite clinical event rate was also reduced for the early initiation group.


Site Licenses

Site license

Site Licenses are available for schools, universities, hospitals, government agencies, and companies. For more information, contact us.