Science-- there's something for everyone

Friday, December 23, 2011

Prevention of HIV infection


By starting anti-retroviral medicines early, heterosexual HIV patients can avoid giving the disease to their partners.  This information could drastically decrease the transmission rate of HIV, turning it from a pandemic to a manageable disease.

Myron Cohen of the University of North Carolina, Chapel Hill and his colleagues screened over 10,000 AIDS patients to find heterosexual couples composed of one HIV-infected and one uninfected partner.  Half of the HIV-positive partners in those 1763 couples were immediately started on a regimen of three daily anti-retrovirals, and the other half did not begin treatment until they became symptomatic.

Over the next three and a half years, there were 28 transmissions of HIV from infected to previously uninfected partners.  Of those, all but one occurred among the couples in the delayed treatment group.  That’s a difference of over 96% between the two treatment groups.  This result was so significant that the study was ended three years early (it was to have run through 2015), and all HIV-infected participants were offered anti-retroviral therapy.  In fact, Science magazine called this study the breakthrough of the year.

I have two comments about this study.  First, you may be wondering why doctors don’t routinely start their HIV patients on anti-retrovirals immediately upon diagnosis.  It simply was not known whether the drugs would be more effective at later stages of the disease. Also, many of these drugs have powerful side effects which patients may wish to avoid as long as possible. 

Second, because all the participants in this study were given standard care and counseling, including free condoms, I find it a bit disconcerting that any of the uninfected partners ended up with AIDS.  At least we now know how to limit that transmission.