HIV Weekly - 20th June 2012

HIV treatment as prevention

An international meeting on Controlling the HIV epidemic with antiretrovirals was held in London last week.

Organised by the International Association of Physicians in AIDS Care (IAPAC), the event looked at evidence for the effectiveness of HIV treatment as prevention and pre-exposure prophylaxis (PrEP), where the same anti-HIV drugs used to treat HIV are used as a prevention method for people who are HIV negative.

There is now clear evidence of ‘treatment as prevention’ (TasP) – in other words, that effective HIV treatment which suppresses viral load reduces the risk of HIV being passed on.

The ‘evidence summit’ also looked at some of the practical and ethical issues raised when countries start planning to use these prevention methods.

For example, although the UK has a good record in enabling HIV-positive people to access health services, and high levels of people with HIV on treatment, rates of testing and diagnosis are not as good. A study by the Health Protection Agency (HPA) has shown that the majority of gay or bisexual men passing on HIV don’t know they are HIV positive.

Increasing the number of people on HIV treatment wouldn’t reduce infection rates in the UK while a large proportion of people with HIV remain undiagnosed. The HPA concludes that improving testing and diagnosis rates is necessary to make a significant difference to the number of infections, and also suggests that these findings highlight the continued importance of condom use as a prevention method.

However, in a session at the summit, Professor Julio Montaner, whose TasP programme in British Columbia, Canada, has been in place for some years, argued that there is enough evidence for TasP’s effectiveness to oblige countries to roll out treatment programmes to everyone eligible for it.

Other delegates argued that making treatment universally available for those who need it for their own health will, by itself, have a significant impact on new infections.

There are still areas of uncertainty, including what the impact of starting treatment early is for the individual; how to support adherence and keep people engaged in health care; the potential impact on HIV-related stigma with more HIV testing and treatment coverage; and concern that sexual risk-taking will increase as a result.

Studies looking at some of these issues are underway.

The summit considered some of the ethical issues raised by TasP, including whether people will be pressurised into starting treatment against their will because of the prevention benefit, especially in parts of the world with fewer, less effective, treatment options available.

For more information, read NAM’s coverage of the IAPAC evidence summit, download our factsheet on HIV treatment as prevention, or visit our online Preventing HIV resource for more detailed information on prevention knowledge to date.

HIV/hepatitis C co-infection and the risk of hip fracture

Hepatitis C infection is already associated with an increased risk of hip fracture. Now a study has found that the risk is increased again by co-infection with hepatitis C and HIV. 

Thinning of the bones is a well-recognised complication of HIV infection. The exact causes are uncertain. However, they could include the direct effects of infection with HIV as well as the side-effects of some anti-HIV drugs, including tenofovir.

The study’s authors call for more research into the causes of this increased risk, but suggest it’s likely to be linked to the inflammatory effects of both conditions. The study, involving over three million people in the US, found that co-infection with HIV and hepatitis C increased the risk of hip fracture even when other factors were taken into account.

However, the researchers also think that social and lifestyle factors have a significant role, with poor nutrition, drug and alcohol use, and the presence of other health problems contributing to the risk of fracture.

For more information on HIV and hepatitis C, read or download our HIV & hepatitis booklet. Visit our website for more information on bone problems.

Adherence and injecting drug use

Providing adherence support to injecting drug users when they start HIV treatment is a key element of helping them achieve an undetectable viral load, a study suggests. 

There is evidence that people who are injecting drugs while they are on HIV treatment can have poorer treatment outcomes, but not a lot is known about the effect of injecting drug use on achieving an undetectable viral load.

This Canadian study involved 267 people who started treatment between 1996 and 2008. They all had a history of injecting drug use; some had injected heroin, cocaine, or a combination of these drugs in the previous six months. Their progress to achieving an undetectable viral load was compared to that of participants who were no longer injecting.

There was no significant difference in rates of viral suppression related to the type of drug injected. However, active injecting drug users were less likely to have an undetectable viral load (56, 58 and 56% of participants who injected cocaine, heroin or both, respectively) than those who didn’t report recent injecting (89%). But this situation changed over time, and in the longer term injecting drug use didn’t affect people’s chances of an undetectable viral load.

A number of factors increased people’s chances of an undetectable viral load, the goal of HIV treatment. These included taking methadone (an opiate substitute), being on a protease inhibitor, and adherence to treatment.

The researchers say their findings show the value of adherence support for injecting drug users, especially when they are first starting treatment.

You can find out more about adherence in our booklet Adherence & resistance. Visit our website for more information on injecting drug use and HIV treatment.