HIV Weekly - 1st May 2013

Treatment as prevention

A large proportion of gay men with HIV take their viral load into consideration when considering the use of condoms during sex, new research shows.

The study involved 177 men with an undetectable viral load.

There’s a lot of interest in the impact of HIV treatment on infectiousness.

Research conducted in heterosexual couples showed that effective treatment that reduced viral load to undetectable levels in the blood reduced the risk of sexual transmission of HIV by 96%.

There’s been little published research on ‘treatment as prevention’ for gay men. However, British HIV doctors recently issued a statement saying that they expected that there would be an extremely low risk of HIV transmission via anal sex if a person has had an undetectable viral load for at least six months and doesn’t have any sexually transmitted infections.

Is knowledge about the impact of treatment on infectiousness affecting decisions about sex?

The findings of this new Dutch study suggest that it is.

Overall, 40% of HIV-positive gay men said they took their viral load into consideration when deciding whether or not to use condoms.

The rate was higher – 63% – among men who reported unprotected sex.

Men were more likely to discuss viral load and risk with partners they knew to be HIV positive than with partners who were HIV negative or of unknown HIV status. This could be because of concerns about disclosure.

There was also evidence that men with the strongest beliefs about the effectiveness of treatment as prevention were most likely to have unprotected anal sex and to cite an undetectable viral load and the low risk of transmission as a justification.

The researchers conclude there’s a pressing need for reliable information about the risk of HIV transmission via anal sex when a person has an undetectable viral load.

For more detailed information on HIV treatment as prevention studies, visit our online Preventing HIV resource.

Sexual behaviour among gay men in the United States

Surveys of gay men in the United States have found significant changes in sexual behaviour over the past decade.

There was a fall in the number of sexual partners reported, especially for younger men. However, condom use remained unchanged.

The surveys were conducted in 2002 and again between 2006 and 2010.

The number of reported sexual partners in the previous year fell by approximately a third.

Rates of unprotected sex, however, remained unchanged. In 2002, 57% of men said they had not used a condom the last time they had anal sex – the corresponding figure for the 2006-2010 period was 58%.

Regular sexual health check-ups are recommended for all sexually active gay men. Approximately a third of men reported a recent check-up in 2002, and this proportion was little changed in the subsequent survey. However, there was a fall in the number of men who reported never having had an HIV test.

Looking after your sexual health is just one aspect of having great sex! For more information, start with our HIV & sex booklet at www.aidsmap.com/booklets.

HIV vaccine trial halted

Health authorities in the United States have halted a study into an experimental HIV vaccine.

The HVTN 505 study started in July 2009 and involved 2504 gay and transgender volunteers in 19 US cities.

However, it has been stopped because an interim analysis showed that the vaccine did not provide protection against infection with HIV.

The rate of new infections after six months was higher among people who received the experimental vaccine compared to people in the placebo arm. Researchers are trying to find an explanation for this.

For more information on vaccine research, visit our online Preventing HIV resource.

Hepatitis C treatment

Researchers gathered in Amsterdam last week for a major conference on hepatitis and the liver.

A number of important studies were presented concerning the safety and effectiveness of new anti-hepatitis C (HCV) drugs.

For the most part, these studies involved people with HCV mono-infection.

The results of several studies were highly encouraging.

Current HCV therapy is based on pegylated interferon and ribavirin. These drugs don't always work and can cause unpleasant side-effects.

But results presented to the Amsterdam conference showed that an interferon-free combination of drugs that work directly against HCV (unlike current therapy) can achieve a 90% cure rate. The study involved people with genotype 1 infection.

Other research showed that a two-drug combination of direct-acting drugs can achieve high rates of sustained virological response (SVR, considered a cure) in people with the easier-to-treat genotype-2 infection.

It seems likely that HCV treatment consisting entirely of direct-acting agents will be a reality within a few years.

Until then, pegylated interferon will remain a mainstay of therapy.

Research presented to the conference showed that triple-drug combinations based on investigational protease inhibitors in combination with pegylated interferon/ribavirin can achieve impressive results. An 80% SVR rate was seen in people treated with a combination incorporating the protease inhibitor faldaprevir. A similar response rate was observed in people taking simeprevir, also a protease inhibitor.

New treatments are also achieving good outcomes in people who did not respond to an earlier course of interferon-based therapy.

However, there was also evidence that triple-drug therapy based on the currently licensed protease inhibitors telaprevir (Incivo) and boceprevir (Victrelis) can involve a high risk of serious side-effects and infections. The research involved people with liver cirrhosis – the group most in need of treatment now and unable to wait for more powerful and better-tolerated drugs.

For more news from the International Liver Congress, visit our conference news pages at www.aidsmap.com/conferences