Doctors fighting HIV/AIDS have a new strategy working for them: Use the treatment of the disease as a way to prevent it – a strategy borne of the growing effectiveness of that treatment in the three decades since the disease first emerged.
Diane Havlir, MD
“Treatment revolutionized AIDS,” says Diane Havlir, MD, professor of Medicine at UCSF and chief of the AIDS program at San Francisco General Hospital and Trauma Center. “Treatment changed AIDS from a uniformly fatal disease to a chronic disease.”
And now, Havlir says, “today’s treatment is also prevention.” Timely treatment can stop the spread of HIV/AIDS in many ways. In patients, it stops the virus from progressing into AIDS, and it prevents damage to organs such as the heart, liver and kidneys, which occurs in untreated AIDS. Treatment also greatly reduces the risk of HIV transmission.
Havlir cites the most encouraging news to date, the National Institute of Allergy and Infectious Diseases - HPTN 052 study, released in May 2011, which reported a 97 percent reduction in HIV transmission among discordant couples – couples in which one partner is HIV-infected and the other is HIV-negative – when the HIV-infected partner is treated with antiretroviral therapy relatively early in the course of HIV infection.
The so-called 052 study – conducted by the HIV Prevention Trials Network (HPTN) – released its results four years early because the prevention effectiveness of the antiretroviral drugs now commonly used to treat HIV infections was so clear-cut.
That news put one more arrow in the quiver of scientists and doctors looking not only to attack HIV, but to stop it.
“Certainly we’re hoping that the next 30 years of HIV can be the last 30 years, especially in San Francisco, where we have the community resources and knowledge to put an end to the epidemic,” says Grant Colfax, MD, director of the HIV Prevention and Research Section in the San Francisco Department of Public Health AIDS Office. Colfax, who trained at UCSF, is adjunct faculty at the university today.
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“We have very good data now that show that when you know your HIV status, and you get treatment if you’re HIV positive, combined with psychosocial supports that decrease stigma, there’s a dramatic decrease in HIV as a result of testing and treatment,” Colfax says.
Employing New Tools, Tactics
Preventing transmission is key to the epidemic in the U.S., where 50,000 new infections per year are still reported. Some of the exciting new tools and tactics employed in the war on HIV and AIDS include:
- Pre-exposure prophylaxis (PrEP). The National Institutes of Health announced in November 2010 that high-risk gay men who take retroviral medication (tenofovir) before they’re infected can prevent HIV infection. While such a strategy is costly, and could be difficult to sustain depending on whether people consistently take the medicine, Colfax hails the study results as “momentous” and says San Francisco is moving forward to test the practicality of this approach.
- CAPRISA microbicides. CAPRISA (the Centre for the AIDS Program of Research in South Africa) announced in July 2010 that when women used an antiretroviral microbicide (tenofovir gel) before intercourse, they significantly reduced their chances of getting HIV. The study was particularly significant because 60 percent of new HIV infections in Africa occur in women and girls. “Microbicide has particular potential among women who may not necessarily be empowered to negotiate condom use with a partner,” Colfax says.
- 052. In the 1990s, when Highly Active Antiretroviral Therapy, or HAART, came into use, the side effects of the drugs was so severe that they weren’t given to people unless they were very ill or had a low level of immunosuppression, as measured by low CD4 count or viral load. The drugs have improved so that now they can be given to people much earlier in the course of the virus. The new HPTN 052 study showed the drugs can also be effective when given to infected people while their immune systems are still relatively healthy. The study was the first randomized study to find that giving antiretrovirals to someone can reduce the risk of sexual transmission of HIV to an uninfected partner.
- Male circumcision. In Africa, as governments begin to promote male circumcision, infection rates are starting to drop, according to Craig R. Cohen, MD, MPH, a UCSF professor and director of Family AIDS Care and Education Services (FACES), an HIV/AIDS care and treatment program in Kenya. Several trials of male circumcision “demonstrated a 60 percent reduction in the number of new infections in men,” Cohen says. World Health Organization guidelines promote voluntary male medical circumcision, and Kenya encourages it as well.
Condoms Cornerstone of Protection
Despite the new tools, some of the best forms of prevention remain the tried and true: Use a condom, and don’t share needles. “Condoms remain a cornerstone of HIV prevention,” Colfax says. “The goal is to provide people with as many prevention options as possible.”
“The most effective way to stop the spread of the disease is to get tested, and if you test positive, get treated.”
Diane Havlir, MD
Even people participating in PrEP and other prevention trials receive condoms and risk reduction messages, he says.
Additional prevention strategies include frequent HIV testing, and if found to be positive, early treatment.
As the stigma associated with AIDS lifts in many regions, more people are willing to take those steps. But in some places, from rural America to Africa, the stigma persists. Many HIV-positive patients show up at the doctor’s office or clinic with late-stage disease, which severely limits the efficacy of treatment.
In San Francisco, “we started a universal HIV treatment program,” says Havlir, whose many hats include director of the AIDS Services, Prevention, Intervention, Research and Education (ASPIRE) Program at UCSF. “We were the first in the world to do this. As soon as an individual is identified with HIV, we are offering treatment for the individual’s benefit.”
Models by UCSF investigators Edwin Charlebois, Moupali Das, Travis Porco and Havlir show that more than just the individual will potentially benefit. “If we treated all persons with HIV currently in care in San Francisco, we’d have a 50 percent reduction in new infections in five years,” Havlir says.
The strategy can have impact well beyond San Francisco.
“African countries struggling with high rates of untreated AIDS stand to benefit enormously from universal treatment,” she says. “Untreated AIDS has massive social and economic collateral damage. People drop out of the workforce, and kids drop out of school to work and support the family. We see all these damages of AIDS and HIV, which our group is postulating can be reversed with universal use of antiretroviral therapies.”
“Everyone says, ‘Oh, antiretroviral therapy is so expensive,’” Havlir says. “Our hypothesis is that it may be the least expensive option, because you get all these benefits. We are working on that with the World Bank, the World Health Organization and others.”
Cohen sees the same thing. “There was a large trial in Uganda, Kenya and Tanzania testing people for HIV – the whole community,” he says. “Once someone tested positive, they immediately started treatment, and did not wait for their CD4 (white blood cell) count to go down. If you bring down a community’s viral load, you can decrease the rate down to almost zero.”
Tests like that show such a strategy may be feasible as well as cost-effective, he says. “You can prevent not just HIV, but potentially other diseases like TB and malaria. And it could improve economic performance in a community where, if someone is infected with HIV, the economic performance goes down.”
The rapid pace of new strategies emerging inspires the researchers to believe that progress will continue, perhaps even pick up speed. “Treatment is prevention,” Havlir says. “We’ve seen it work and it’s a critical part of the strategy to end the AIDS epidemic.”