News from the International AIDS Conference

This edition concentrates on relevant research from the 20th International AIDS Conference (AIDS 2014), held in Melbourne, Australia at the end of July. For all our news reporting from the conference, visit

Comparing London and San Francisco

Researchers from London and San Francisco presented a comparison of the HIV epidemics among men who have sex with men in each city. Whereas HIV prevalence has historically been far higher in San Francisco (24%) than in London (13%), the rates are now falling in San Francisco. The researchers wanted to better understand the reasons for the American city’s success.

In San Francisco, both the estimated incidence (rate of new infections) and recorded number of new diagnoses have been falling since 2007, whereas these figures have either remained static or risen in London.

Why? The most obvious difference is in the proportion of gay men who know their HIV status. Although around half of Londoners claim to have tested recently (in surveys done on the gay scene), figures on the actual number of tests done at GUM clinics would suggest that only 17% test each year. Rates are much higher in San Francisco. San Francisco had a particularly sharp drop in the proportion of gay men living with HIV who are undiagnosed, from 22 to 4% between 2004 and 2011.

In both cities, similar numbers of men report sex without condoms. But higher testing rates in San Francisco apparently lead to higher rates of HIV status disclosure between gay men and, as a result, much higher rates of serosorting that is based on men’s actual HIV status (rather than guesses). There was a falling rate of unprotected sex with partners of opposite or unknown status in San Francisco compared with no change in London.

The analysis suggests that very high rates of HIV testing, awareness, and disclosure of HIV status can play a critical role in HIV prevention. But a culture of openness about HIV-positive status may be more achievable in a city where one-in-four gay men are living with HIV. Can London achieve San Francisco’s culture of testing and disclosure in a larger, lower-prevalence population?

Drugs and sex

The probability of gay men in England having unprotected anal intercourse is strongly associated with the number of recreational drugs they have taken at the time, according to a new study.

Although the finding will confirm many people’s common sense beliefs, it has not previously been demonstrated in UK research. Previous studies have found associations between men using drugs at least once in the past few months and men having unprotected sex at least once during that period – but have not analysed their interaction during a single event.

Whereas there was a 25% probability of unprotected sex when no substances were used, this rose to 30% when one substance had been taken, 50% with three substances and a 75% probability of unprotected sex when more than five substances had been taken.

Poppers, GHB and crystal methamphetamine were the drugs most frequently associated with unprotected sex. But while men were less likely to feel ‘in control’ of what they were doing if they had taken crystal meth, other drugs were not associated with feeling ‘out of control’. In other words, the link between drug use and risky sex is more complex than drugs leading to men being unaware of what they are doing sexually.

Treatment optimism

It is sometimes suggested that people who are taking HIV treatment will be less worried about transmitting HIV and so less likely to use condoms. This idea is known as ‘treatment optimism’ or ‘risk compensation’, and is also a concern raised in relation to the use of pre-exposure prophylaxis (PrEP) by HIV-negative people.

But a systematic review and meta-analysis of studies of heterosexual people in low- and middle-income countries (mostly in Africa) has not found any evidence for this. Each study either compared sexual risk behaviour in people on treatment with people not on treatment, or in the same people before and after starting treatment.

In fact, the analysis consistently found that people who were taking treatment were more likely to use condoms than people who were not. Treatment was associated with an increased likelihood of consistent condom use (odds ratio 1.8) and of using a condom the last time a person had sex (odds ratio 2.3).

This was the case for both men and women; for committed relationships and casual sex; and for partners both known, and not known, to be HIV negative.

The results may suggest that instead of ‘treatment optimism’ causing complacency, the provision of HIV treatment could lead to decreased HIV risk behaviour due to regular medical contact and counselling, as well as being linked with an increased hope for the future and a sense of agency. The researchers said that the findings show that the phrase ‘treatment as prevention’ may be true in more ways than one.

Couples counselling and testing

Research conducted in Zambia has found that couples voluntary counselling and testing can reduce new HIV infections (incidence) within relationships.

The intervention involves couples being counselled together, taking HIV tests together, and being counselled together on the implications of the results, whatever they are, afterwards. The process aims to reduce tension, diffuse blame, and create an environment in which HIV status can be disclosed safely.

Approximately 150,000 couples have received couples testing in Lusaka, Zambia. Previous surveillance in Zambia had shown that in couples of differing HIV status, annual HIV incidence in the HIV-negative partner was 11% (i.e. one in nine acquired HIV per year). But after couples testing, incidence dropped to 2% a year (i.e. one in 50 of the HIV-negative partners acquired HIV a year) – an 82% decline in incidence.

A similar decline in incidence was observed in couples who were both HIV negative.

For couples in which one person was living with HIV, the couples counselling and testing appeared to help people take and adhere to HIV treatment – probably by promoting disclosure of HIV status and encouraging partners to support each other with adherence. In couples where HIV status had not been disclosed, adherence was quite poor.

A case study in a previous edition of this bulletin reported on LASS’ experience of couples testing in Leicester, but in general it is not an approach that has been sufficiently explored in the UK.


The effectiveness of pre-exposure prophylaxis (PrEP) is strongly dependent on adherence, results of an extension to the iPrEx study show.

The study compared infection rates among individuals taking PrEP and individuals who chose not to take it. It provides the first effectiveness results from a large, open-label study of PrEP where participants knew they were not taking a placebo.

A total of 1603 men who have sex with men (MSM) and transgender women were recruited to the study, 1225 of whom chose to take PrEP.

Participants were followed for up to 72 weeks. Overall, taking PrEP reduced the risk of acquiring HIV by half. But the effectiveness of the treatment was related to adherence.

The treatment had no impact on the risk of infection for participants who took fewer than two doses a week. For participants who took two to three weekly doses, the treatment reduced the risk of acquiring HIV by 84%. No HIV infections were seen in the sub-group who took four or more doses a week. But only a third of participants managed such a high level of adherence.

Adherence was strongly associated with age: study participants in their 30s and 40s were two or three times more likely to have detectable levels of PrEP drugs in their blood compared to younger people.

The researchers also calculated that only 39% of participants at high risk of HIV at the start of the study were taking enough PrEP doses to protect them against HIV three months later. The number of people who were not motivated enough to take PrEP consistently may show that PrEP is not a practical option for some people who are at risk, or that more sophisticated support is needed.

PrEP was an important theme at the conference:


The Melbourne conference also heard a number of presentations and studies about self-testing (home testing). The World Health Organization (WHO) and Joint United Nations Programme on HIV/AIDS (UNAIDS) both believe that self-testing will have a place in future strategies, although they say that there isn’t enough research evidence yet to inform guidelines. In particular, the evidence of effective systems to promote confirmatory testing, linkage to care and retention in care following self-testing is limited.

It’s not clear how self-testing will be made available, but WHO have begun to scope out some of the possibilities:

  • Open-access and unsupervised, with sales or distribution through retail pharmacies, websites or vending machines (the dominant model in the United States).
  • Some restrictions on access, with tests available from outreach workers, pharmacists or clinicians. Eligibility criteria might be more or less strict, depending on national policies and the epidemiological context.
  • Supervised self-testing, with additional support from a health worker or community volunteer, such as a demonstration of how to use the test or referrals to additional services.

At present there is only one self-test kit that has been licensed by a respected regulatory body and is commercially available (the OraQuick test in the United States). But there are considerable challenges to bringing new self-test kits to the market. From the point of view of a commercial manufacturer or distributor, there are many uncertainties and therefore few incentives to be the first company to launch a product. The size of the market is difficult to estimate, efficient distribution systems do not yet exist, national HIV programmes haven’t defined the role of self-testing, and regulatory processes are often unclear or complex.

HIV prevention for black African people in the UK

NAT (National AIDS Trust) argues in a recent report that although black African communities in the UK are disproportionately affected by HIV, their HIV-related needs have not received the attention or the resources they should from policy-makers, decision-makers and funders. In particular, NAT believes that HIV prevention activities are under resourced, do not achieve sufficient local coverage and need to be scaled up. Implementation is characterised as "stop-start".

NAT also argue that there is a lack of robust and independent evaluation of prevention work, which hinders the development of a shared knowledge-base of which interventions work and of the ways in which they work. 

They report that a recurring theme among the stakeholders they consulted was the dislike of HIV prevention activity which singles black African people out as the one ethnic group amongst heterosexual people who are at risk of HIV. The question of “targeting” must be sensitively handled, they believe, suggesting that interventions which reach black African people should be integrated with wider work for the sexually active heterosexual population.

NAT’s report also criticises the failure of primary care and other NHS services to implement guidelines on HIV testing. As a result, rates of late diagnosis remain considerably higher in African people than in other communities.

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