A clinical trial involving AIDS this year is rightly being called by Science magazine the most important scientific breakthrough of the year.

When the study on the benefits of antiretroviral therapy ran last August in the New England Journal of Medicine, it did not really get the attention it deserved, possibly because news headlines are too often drawn to human failure, evil and the miserable.  However, researchers convincingly showed that people who take antiretrovirals  -- medicine that weakens the HIV virus -- not only benefit from treatment but are far less likely to sexually infect their non-HIV positive wife or partner. 

How much less? Try 95 percent!

Myron Cohen of the University of North Carolina's School of Medicine, and an international team of colleagues, started looking at the impact of medicine on disease transmission back in 2007. They studied more than 1,700 heterosexual couples from nine different countries: Brazil, India, Thailand, the United States, Botswana, Kenya, Malawi, South Africa and Zimbabwe. Each couple included one partner with an HIV infection, one not.

They found that AIDS medicine reduced the amount of virus in an infected person’s body -- not news there. But the meds reduced the amount of virus in the infected person to the point where giving it to others through sexual activity was greatly diminished.

So, at last, after taking a terrible toll on us for decades, we now know how to get the HIV virus on the run. Get anti-retroviral medications to all 7.6 million people who need them, continue aggressive efforts to promote the use of condoms and the avoidance of risky sexual and injection drug behavior, give out clean needles to addicts and we can have our revenge on the virus that causes AIDS.

Art Caplan, Ph.D., is the director for the Center for Bioethics at the University of Pennsylvania.  Follow him on Twitter @ArthurCaplan. 

Read more columns by Art Caplan:

Shame on school for rejecting boy with HIV

Vatican push for adult stem cells can't ignore good science