Treatment as prevention – Festina Lente (hasten slowly)

HIV Australia | Vol. 10 No. 1 | June 2012

Sean Slavin says that population health benefit should not eclipse the needs of individuals when considering treatment as prevention.

Two years ago I wrote a chapter for an AFAO monograph on treatment as prevention that welcomed the news that antiretroviral treatments (ARVs) have a preventative effect on transmission but noted the paradoxical nature of the technology in the context of a set of changing relationships to risk in the sexual lives of gay men.¹

I argued that at the heart of this paradox lies the distinction between individuals and populations and the fact that interventions designed to have a population benefit might not be sufficiently effective for individual use. Much of the discussion in the past two years about biomedical prevention technologies in Australia has, implicitly if not explicitly, occurred in the context of population benefits and risks. I maintain that the preventative effects of HIV treatment should be warmly welcomed, however there is a need for ongoing consideration of the meaning of these technologies for individuals and communities.

No ‘one size fits all’

In thinking about whether to use treatment as prevention as an individual strategy, a person might ask: ‘Will it work to prevent me passing on HIV to my partners?’ The answer to this will be a cautious ‘yes’ circled with a number of caveats, the most significant for gay men being ‘we only have good evidence of this in the context of heterosexual sex.’

If it’s a gay person asking, then the honest answer must currently be something like: ‘It will work to reduce the risk of transmission. To what extent, we don’t know and its effectiveness is probably influenced by a range of other factors including the presence of STIs.’

So given that the risk of transmission in the second case is located somewhere on a sliding scale –but the outcome, HIV infection, is something that is absolute (you either have or you don’t) –if you absolutely want to prevent HIV transmission then you would be well-advised not to rely solely on this approach.

If you are prepared to entertain the idea that transmission might occur, then this approach may help to make this less likely. Entertaining the idea that transmission might occur would hopefully be a decision made after careful consideration of the long-term ramifications.

If the question about whether treatment as prevention is asked in relation to populations there are a different set of theoretical answers that depend on the scale of HIV testing and the uptake of treatments across the population.

Given that incident HIV infections in Australia continue to occur at the same or increased rates as in the past it is safe to assume that we have not yet achieved high enough rates of testing or treating. But how much is enough to have an effect on HIV incidence?

According to modelling done by David Wilson at the Kirby Institute for infection and immunity in society, in order to achieve a 50% reduction in new infections over two years we would need to increase testing four-fold and increase the proportion of people on treatment from 70% to 90%. According to the proponents of the test and treat idea, if you achieve universal coverage of both, then HIV can be eradicated in a population.²

Now, this is the sort of talk that gets blood rushing to the heads of those in public health, reminding them of the golden age of mass vaccination. But antiretroviral therapy is patently not a vaccine. Even the simplest drug combinations require daily dosing and better than 95% adherence, for a lifetime.

In whose interest?

I think we conflate individual and population discussions of HIV treatment at our peril. For example, a public health approach may say that treatment should be started as soon as possible after diagnosis in order to reduce the risk of onward transmission, regardless of whether treatment is clinically indicated.

It is argued that viral load is often extremely elevated during acute infection (although only a small proportion of diagnoses are made during this stage) and there is a high risk of secondary infection. Reducing viral load would reduce this risk. There are several serious problems with this proposal.³

First, viral load does not drop instantly once treatments are started. In most individuals it takes many weeks (if not several months) to achieve an undetectable viral load. So while there may be a theoretical population benefit in treating at this point, individuals would be ill-advised to rely on this approach to prevent transmission.

Second, there is currently no evidence to support an individual health benefit for starting treatments before CD4 cells fall below 500/ìl.⁴ Many clinicians are uncomfortable making treatment recommendations on grounds other than individual patient need.

Third, this approach implicitly diminishes the potential benefits of less invasive interventions such as education and counselling. By fully discussing the increased risks of onward transmission with those diagnosed during the acute phase of infection, behaviour change that includes strict adherence to condoms or abstinence for a period becomes available.

Fourth, this proposition about the higher levels of infectivity during primary infection is based on limited evidence. On the face of it, it seems plausible, but do we base a major prevention intervention on an idea that seems plausible?⁵

The decision to start treatment is almost always a weighty one, which should not be rushed if the best possible long-term outcome is to be achieved. Receiving an HIV diagnosis is still difficult and traumatic for most people and for many there is no great urgency to start treatment immediately. Why conflate the two issues and risk exacerbating the trauma of diagnosis and creating a negative impression of treatment?

Complex decisions and subtle pressures

While I don’t think there’s any real risk of coercive treatment in Australia, people living with HIV nonetheless endure subtle pressure that places them in a position of greater responsibility for prevention. .

An example in the United States was the campaign ‘HIV stops with me’ (hivstopswithme.org) which was underpinned by the Center for Disease Control’s position on positive prevention that emphasises disclosure and personal responsibility.⁶ Using treatment to affect the spread of HIV would likely involve aspects of this approach.

Notwithstanding some of the reservations I have about the effectiveness of treatment as prevention, I do wish to acknowledge that, for many people living with HIV, an undetectable viral load allows them to feel less infectious and less anxious about transmitting the virus to sexual partners. This is obviously a good thing, if it’s a second order outcome of a decision to treat. It’s obviously problematic if the person with HIV feels obligated to treat.

We should also be cautious in ascribing this anxiety to all people living with HIV, or assuming that taking treatments will necessarily alleviate the anxiety. In research conducted by NAPWA (National Association of People Living With HIV/AIDS) and the NCHSR (National Centre in HIV Social Research) that is currently being analysed about experiences of HIV stigma, we have found HIV-positive people expressing internalised stigma in forms such as ‘feeling dirty’ or ‘feeling infectious’.

However, when we look at whether these feelings occur more often among those not on treatment, there appears to be no correlation. Likewise, for many HIV-positive people, adherence to safe sex is adequate to reduce their anxieties about transmission.

Another issue raised by the idea of treatment as prevention is how we understand and talk to people withHIV who do not take treatments. It is estimated that approximately 30% of people living with HIV do not take ARVs and we currently understand little about their thinking or motivations.

While we await data on this group, I can only bring to mind friends who have decided for the moment not to treat. These people have not made these decisions out of ignorance. They are well-informed about both HIV disease and treatments and don’t hold any radical unscientific views along the lines that HIV doesn’t cause AIDS.

In fact they hold very normal beliefs about staying well by maintaining a healthy lifestyle, as well as reservations about putting serious drugs into their bodies unless they are absolutely warranted and fears that regular pill taking will have a significant impact on their lifestyle. These people monitor their CD4 and have ongoing relationships with a doctor.

People like this are acutely aware of the complexity of treatment decisions and it would be inaccurate to regard them as suffering a deficit of knowledge or holding irrational beliefs. In the end it surely must be the right of any person with HIV to make a decision in relation to treatments that we may disagree with.

A related issue is the question of people who do take treatment but cannot achieve an undetectable viral load (about 12%).⁷ Does this represent a failure of treatment as prevention? What should we be advising these people about the transmission risks of having a detectable viral load?

In the discussions occurring across the sector about combination prevention or more optimistically the ‘prevention revolution’, we have quickly become accustomed to the mantra that biomedical technologies are options to be used in addition to condoms. But how realistic is this for individuals?

Why would an HIV-negative gay man use PrEP (pre-exposure prophylaxis) and condoms? If treatment as prevention really works, why would serodiscordant couples continue to use condoms? The reality is that most people will identify these things as alternatives. Some will gladly abandon condoms while others may be cautious about embracing drug-based technologies that are arguably much more interventionist.

It remains to be seen what the social or community effects will be when some gay men choose to stick with condoms while others opt for different technologies. Given that stigma still exists around HIV in sexual contexts, will these technologies make this better or worse? Will HIV-positive people who are not on treatments become sexual pariahs?

Conclusion

I reiterate that realising HIV treatments have preventative effects has been overwhelmingly positive and this development should be welcomed. However, when scientists at the International AIDS Society Conference in Rome last year made the astounding claim that ‘treatment is prevention’ this should sound some warnings for us in the community sector.

We should remember that prevention is something we’ve been doing very effectively for 30 years within gay communities. While we have spent quite a bit of energy in the past decade trying to understand what’s wrong with condoms as a prevention tool, we perhaps also need to spend energy understanding what’s right about them for a significant proportion of gay men.

Further, I think whenever science declares it has found the silver bullet we should maintain our scepticism, openness to dissenting views (including ‘non-scientific’ community views) and confidence in our experience of knowing what already works.

Prevention has not become simpler because of scientific discoveries in recent years, risk has become infinitely more complex. It is more important than ever that community based organisations remain central to interpreting these developments and communicating with real life individuals in the community about how to prevent HIV. Quite a different conversation to the ones we have with scientists and funders about reducing population level risk.

References

1 Murphy, D. [ed.]. (2010). Trick or Treat? Antiretroviral therapy as HIV prevention. AFAO Biomedical Prevention Monograph No. 1. Australian Federation of AIDS Organisations, Sydney.

2 Granich, R., Gilks, C., Dye, C., De Cock, K., Williams, B. (2009). Universal voluntary HIV testing with immediate antiretroviral therapy as a strategy for elimination of HIV transmission: a mathematical model. Lancet, 373, 48–57.

3 Fidler, S., Fox, J., Porter, K., Weber, J. (2008). Primary HIV infection: to treat or not to treat? Curr Opin Infect Dis, 21, 4–10.

4 Bell, S., Little, S., Rosenberg, E. (2010). Clinical management of acute HIV infection: best practice remains unknown. J Infect Dis, 202, Suppl 2, S278–S288.

5 Myron, S., Cohen, M., Shaw, G., et. al.(2011). Acute HIV-1 Infection. N Engl J Med, 364, 1943–1954.

6 Centers for Disease Control and Prevention. (2003). Advancing HIV prevention: new
strategies for a changing epidemic. MMWR, 52(15), 329–32.

7 The Kirby Institute. (2011). The Australian HIV Observational Database Annual Report. Volume 11, Number 1. The Kirby Institute, University of New South Wales, Sydney. Retrieved from: http://www.med.unsw.edu.au (PDF)

Sean Slavin is Assistant Director and Manager of Research Programs at the National Association of People Living with HIV/AIDS (NAPWA).