AIDS and global health

Haley Bridger, December 3rd, 2010
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Last month, we wrote about results from a collaborative project at the Broad Institute and Ragon Institute of MGH, MIT, and Harvard that aims to discover why some people can keep HIV in check, with the ultimate goal of finding insights that could help scientists build an HIV vaccine. Researchers at the Broad are tackling this mystery by examining genetic clues in people as well as their viral populations. In human DNA, researchers have homed in on a protein that plays a key role in immunity: HLA-B. Meanwhile, Broad researchers involved in the Broad’s Viral Genomics Initiative are looking at how HIV adapts to evade the immune system’s defenses. Ultimately, researchers want to design a vaccine that can elicit an immune response that forces the virus into a space where it cannot mutate and escape.

There are many challenges that stand in the way of a vaccine, and as the world continues to wait for one, doctors in the field must find ways to help patients and prevent AIDS from spreading further. Earlier this week at the Harvard School of Public Health, a panel that included three doctors, a student, and an esteemed researcher spoke about preventive efforts that are currently underway.

All of the speakers emphasized the importance of adding new strategies to the arsenal of prevention techniques. They noted that until a vaccine becomes available, we will need combinations of all of the strategies below in order to help contain the spread of the disease.

Protective pill: Last month, exciting reports emerged about a pill that can be given as a prophylactic (before exposure to HIV). The men enrolled in the study were at particularly high risk for contracting AIDS. The 2,500 participants didn’t just take one pill a day (either a placebo or the anti-retroviral drug tenofovir) – they were also tested monthly for HIV as well as other sexually transmitted infections and received counseling. Those who took the pill on 90 percent or more of the days of the trial had 72.8 percent fewer HIV infections. The main drawbacks to this strategy known as PrEP (pre-exposure prophylaxis) are access, cost, and compliance – patients who stopped taking the drug or kept missing doses didn’t reap its full benefits.

Protecting women: Researchers have been developing a vaginal microbicide gel that women can apply before and after sex. In July, clinical trials showed that this gel (made from tenofovir) reduced women’s risk of HIV infection by 39 percent, results that will need to be confirmed in future studies. The goal is to mass produce the gel in a few years and offer it at a cost of as little as 25 cents per application.

Preventing mother-to-child transmission of HIV: There are 2.5 million children living with HIV today. Ninety percent of these infections were passed from mother to child during pregnancy, delivery, or while breastfeeding. But mother-to-child transmission is almost entirely preventable thanks to antiretroviral drugs, which can help keep a mother’s viral load low. In the United States, the prevention of mother-to-child transmission is one of the greatest HIV success stories: in 1994, 560 children in the United States died from AIDS but by 2008, that number had dropped to five. But mother-to-child transmission remains a problem globally: worldwide, it’s estimated that 370,000 children were newly infected with HIV in 2009. The challenge will be bringing strategies that prevent this kind of transmission to the countries that need them most.

Education: Perhaps the most obvious but overlooked strategy in preventing the spread of HIV is educating men and women in this country and around the world about how to protect themselves and decrease their risk of infection. Stella Safo, a fourth-year medical student at Harvard Medical School, has spent time in both Ghana and Boston leading educational programs. She noted that there is a continued need for education, especially as treatment options advance – as our understanding of HIV and AIDS increases, our complacency may grow as well.