Treatment as Prevention and More

While widely available antiretrovirals help HIV-infected people in developed countries live into their golden years, overall life spans are far shorter in many developing countries, often due to the overwhelming numbers of new infections. But programs based on new research may prevent infection in places like sub-Saharan Africa, which currently accounts for 65 percent of all new HIV infections worldwide.

Results from a major 13-site trial found in May that starting antiretroviral therapy (ART) early greatly reduced transmission rates. David Celentano, ScD ’77, MHS ’75, led research involving heterosexual partners in Thailand, where one partner was already infected. A group receiving treatment when their CD4 counts were above 350 cells/mm3 were compared to those who delayed starting treatment until their CD4 counts dropped to current WHO guidelines of 250 or below. Of 28 subsequent partner-to-partner infections, only one came from the early treatment group.

“USAID is very aware of the findings,” says Celentano, the Charles Armstrong Chair and Professor of Epidemiology. “They recognize that [early treatment] could be one piece of eliminating HIV.” At an estimated cost of $100 to $300 per person per year for ART treatment, Celentano sees using treatment-as-prevention as being financially prudent. “If you look at potential years of life lost, disability-adjusted life years lost [to each infection]…it’s just a massive amount of savings.”

At a lesser one-time cost—$30 to $60 per surgery—male circumcision continues to show promise for reducing lifelong risk of acquiring HIV infection. Five years after a breakthrough study of thousands of Ugandan men showed that circumcised males were half as likely to contract HIV as an uncircumcised control group (findings that were bolstered by similar studies in Kenya and South Africa), a recent follow-up report found evidence of lasting protection. Looking at new HIV infections among the same original groups, Bloomberg School researchers found that the circumcised men were 73 percent less likely to have acquired HIV than their uncircumcised brethren.

The focus now is on making the surgery quicker, safer and less expensive. Epidemiology professor Maria Wawer, MD, MHSc, says they’ve received an NIH grant for testing a ring-type surgical device in Uganda that “would cut surgical time down from 25 to five minutes.”

Ronald Gray, MD, MSc, admits, “It’s a pretty radical change in strategy for public health to be promoting surgery for the prevention of an infectious disease.” Still, Gray, a professor in Epidemiology, adds that the Ugandan, Kenyan and South African governments now endorse circumcision, and that, short of an HIV vaccine, circumcision offers something unique with regards to the prevention of HIV and a number of other sexually transmitted infections.

“Frankly,” he says, “there’s nothing else I know of [in which] a one-time procedure can substantially reduce your risk of acquiring an infectious disease for a lifetime.”