Call for Treatment as Prevention
posted: 10/03/2009
Pioneers in HIV research now call for testing of a strategy that uses treatment-as-prevention deserves testing out.
One of the pioneers of HIV research, former Harvard retrovirology professor William Haseltine, said today that universal testing and treatment now offers the best hope of controlling the HIV pandemic.
Writing in the news magazine The Atlantic, Haseltine said that three other authorities involved in the discovery of HIV – Robert Gallo, Max Essex and Robert Redfield – have reached the same conclusion.
“History has shown that epidemics can be controlled, even in the absence of a vaccine,” he says. “Both syphilis and tuberculosis were pandemic at the end of the nineteenth century, and both epidemics were controlled by effective diagnosis and treatment.”
Global call for new treatment-as-prevention strategy
“I recommend that WHO, PEPFAR and the Global Fund begin studies to assess the effectiveness of universal testing and early treatment for the prevention of HIV transmission,” he urges.
Vaccines doubts
At a recent seminar on global governance challenges at the James Martin 21st Century School at Oxford University, Professor Jonathan Weber of London’s Imperial College said that after 27 years in HIV research, he no longer believes a vaccine to be achievable. Instead he believes that population-based antiretroviral therapy (PopART) is the only strategy currently available that holds out the prospect of HIV eradication.
WHO - S Africa and UK
Population-based treatment, or maximising the numbers testing and on treatment, is a subject of growing interest to researchers. Last November the World Health Organization published details of a mathematical modelling exercise which suggested that if all people in South Africa could be diagnosed and begin antiretroviral treatment within a year of infection, the number of new infections could be reduced by 95% within ten years. It also looked at its use in the UK.
Montreal conference calls
Then at the Sixteenth Conference on Retroviruses and Opportunistic Infections in Montreal, Canada earlier this month, two studies of transmission risk in HIV-discordant couples were presented. One showed no cases of transmission in couples where the HIV-positive partner took antiretrovirals, while the other showed an 80% reduction in transmission risk.
Christophe Fraser, an epidemiologist from Imperial College, London, warned the confererence that the striking effect of universal treatment in mathematical models might not be replicated in real life if it proved less than 99% effective, and called for careful examination of the assumptions in the WHO models by other epidemiologists before policy is made.
Brighton CHAPS conference calls
And the recent UK gay men's sexual health conference CHAPS, in Brighton debated this. George House Trust's policy expert Chris Morley was one of a panel of speakers debating Treatment as Prevention.
Many people with HIV on treatment with an undetectable viral load are already rethinking condom use and telling partners. There are still some risks of HIV transmission - particularly if either partner has a sexually transmitted infection. But in ideal circumstances, it is pretty clear that the transmission risks with an undetectable viral load are not much worse than with using condoms consistently. People have a right to know the facts and to choose how to manage transmission risks and disclosure to suit themselves.
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Undetectable But Infectious?
posted: 10/02/2009
One of the hottest topics over the last twelve months has been the infectiousness (or otherwise) of people taking HIV treatment who have an undetectable viral load in their blood.
The debate was kick-started a year ago by what’s come to be known as the “Swiss Statement”. This said that individuals taking HIV treatment who had an undetectable viral load and no sexually transmitted infections were essentially non-infectious to their partner in a monogamous heterosexual relationship.
The authors of the Swiss Statement noted that effective HIV treatment suppressed viral load to undetectable levels in both blood and semen.
However, two studies presented to the CROI Conference in Montreal, Canada, have confirmed that HIV can be undetectable in blood, but still detectable in semen in a minority of men, even without any STIs.
1 in 7 "undetectable" men have detectable and infectious semen
A Canadian study involving 25 men found that undetectable viral load in the blood, was found with detectable virus in about 1 in 7 semen samples. The virus in semen was potentially infectious.
Semen virus sometimes blips and becomes detectable
The study also showed that viral load in semen occasionally “blipped” to detectable levels.
About a third of men who’d been taking long-term HIV treatment that suppressed viral load to undetectable levels in the blood occasionally had detectable HIV in their semen.
A larger French study looked at paired blood and semen samples from 145 men taking HIV treatment. Viral load was undetectable in 85% of these paired samples. But in 3% of samples, HIV was undetectable in blood and detectable in semen – viral load in these samples ranged between 250 and 1200 copies/ml.
Most of these detectable samples were “blips”, and the French researchers found good levels of anti-HIV drugs in the patients’ semen.
There was discussion about the implications of these findings, in particular if the levels of HIV found in semen involved a significant risk of HIV transmission. There was only one case of HIV transmission in the French study, but this involved a patient who wasn’t taking his treatment properly.
Swiss should not claim undetectable people can never transmit
However, both sets of researchers concluded that an undetectable viral load in blood doesn’t always mean that viral load is undetectable in semen, and that successful HIV treatment doesn’t entirely eliminate the risk of HIV transmission. So the Swiss statement was a bit too dogmatic - transmission is possible but seems really unlikely.
You can sign up for NAM's CROI conference dailiy update here
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