In a November 29, 2006 presentation to a UCSF epidemiology class, Dr. Willi McFarland of San Francisco General Hospital said that the North American prevalence of heterosexual HIV transmission is almost exclusively concentrated in the intravenous drug user population. The rapid decrease to near extinction of HIV infection among heterosexual groups in San Francisco has been the city’s policy of providing needle exchange to this high risk group.
These insights virtually rule out circumcision as a cost effective measure against HIV infection in the North American context, not only because needle exchange is inexpensive and avoids the numbers-needed-to-treat conundrum, but also because intravenous drug users are small in number and reachable. [See this excellent discussion on the numbers needed to treat in the circumcision/HIV context.]
In response to a question viz. the falling rates of infection among intravenous drug users being due to needle exchange, Dr. McFarland said:
San Francisco was more progressive than most of the country in this regard. [Needle exchange] was implemented early despite the laws [that] didn’t change, but San Francisco does this, supports it, ongoing. We can’t use federal money, so it is a very proactive effort to sustain needle exchange. I think it was a case of doing the right thing at the right time. And it isn’t just among injectors. The heterosexual epidemic in North America follows the injection epidemic. [Heterosexual transmission] really isn’t much from bisexual men. So by preventing it among injection drug users, we prevent it among heterosexuals, we prevent it among women, we prevent it among children. … If we want to prevent it among women and children, this is the way to do it.
Dr. McFarland’s talk was presented as part of the San Francisco General Hospital Positive Health Program Grand Rounds.
McFarland, Willli, MD, Ph.D. HIV/AIDS Epi-Update for San Francisco. HIVinSite Featured Content. November 29, 2006.