New diagnoses of HIV and STIs

Public Health England (a new body which includes the former Health Protection Agency) has released a report on HIV in London, showing that half of the UK’s new HIV diagnoses are made in the capital. Men who have sex with men and who are newly diagnosed with HIV tend to live in central and inner London boroughs, whereas newly diagnosed heterosexual people are dispersed across the capital.

Although undiagnosed infection and late diagnosis are common, only one in three primary care trusts in high-prevalence boroughs commissioned routine HIV screening in primary care in 2012; one in five commissioned tests for new medical admissions.

In 2011, there was a modest fall in new HIV diagnoses in London (2637 diagnoses, 4% less than in 2010). This was attributed to changing patterns of migration, with fewer diagnoses in black African people. The number of new diagnoses among men who have sex with men actually increased between 2010 and 2011, and there was also a modest increase in the number of diagnoses due to heterosexual transmission that occurred in the UK.

Public Health England also released data showing that there were just under half a million new diagnoses of sexually transmitted infections (STIs) in 2012. As in previous years, there were particularly high rates in men who have sex with men and in young heterosexual adults, with some urban areas having a much greater burden of disease than other parts of the country.

More encouragingly, rates of genital warts are down in young women – apparently because of the human papillomavirus (HPV) vaccination programme.

Both reports draw attention to variations in the burden of sexual ill health and in the coverage of screening interventions in different parts of the country. These data should guide local authority decisions about commissioning screening and testing services.

Improving HIV testing

Dramatic improvements in the offer and uptake of HIV testing are possible, but require local leadership, strong commissioning and multiple initiatives, report clinicians in Brighton & Hove.

Over the last few years, the city has placed a strong emphasis on expanding HIV testing, with numerous educational interventions for non-specialist clinicians, service innovations and research studies. General practitioners (GPs) have been trained to recognise the symptoms of primary HIV infection and are offered free HIV testing kits. Rapid testing has been in offered in gay community settings.

The proportion of new HIV diagnoses which are made outside of sexual health and antenatal clinics has increased from 26% in 2000 to 58% in 2012, driven by improvements in HIV testing in primary care and community settings. Diagnoses in hospital settings have increased to a lesser extent.

The number of people diagnosed with recent infection or with seroconversion symptoms has increased dramatically. This is largely due to GPs now being more aware of these symptoms.

Late diagnosis rates have gone down.

The researchers recommend that in each local area, sexual health clinicians should work with and support colleagues in primary care, secondary care and voluntary organisations in order to improve testing practices.

PrEP works for injecting drug users

A large study has found that a daily antiretroviral tablet taken as pre-exposure prophylaxis (PrEP) significantly reduced the risk of HIV acquisition among people who inject drugs. As in PrEP studies to prevent sexual transmission, those who took the medication most consistently had higher levels of protection. The seven-year study was conducted in Thailand.

Half the participants took tenofovir and half took a placebo (dummy pill). Most individuals came into a clinic each day to receive their medication from a nurse and received a 70 baht (£1.40) financial incentive each time they did so. Perhaps because of this, adherence and retention was relatively good for a cohort of injecting drug users.

Fifty of the 2413 participants became HIV positive during the study – 17 were in the PrEP group, and 33 were in the placebo group. This amounts to PrEP preventing half (48.9%) of new HIV infections.

Researchers are calling this a significant step forward for HIV prevention. PrEP has now been shown to reduce infections in several key populations – injecting drug users, men who have sex with men, heterosexual serodiscordant couples and infants (vertical transmission). However, studies with young African women have had disappointing results, because few of the women actually took the drug regularly.

American public health officials have already issued guidance recommending that PrEP is provided to injecting drug users. But scientists and activists are also saying that PrEP should not be seen as a replacement for needle exchange programmes which are politically controversial in many countries (but not the UK). When provided, PrEP should be part of a combination package of interventions, including needle exchange and opioid substitution therapy.

Deciding what’s risky

A new study has examined HIV-negative gay men’s perceptions of the risk of HIV transmission during different sexual activities. The study was done because, although scientists’ understanding of this topic has become increasingly complex, little is known about whether this information is understood or acted upon by gay men.

The research was conducted in Sydney, Australia, where HIV prevention organisations have generally been more upfront in their discussions of non-condom based risk-reduction strategies than organisations in the UK.

Men were asked to rate the risk of HIV infection in a series of situations. Their responses broadly reflected scientists’ understandings – for example, most men believed that unprotected anal intercourse is riskier for the receptive rather than the insertive partner.

Respondents took account of both the specific sexual act and their partner’s health status in their assessments of risk. But men paid considerably more attention to condom use, withdrawal and sexual role than they did to their partner’s reported HIV status or viral load.

This confirms other research showing that HIV-negative men are not as confident as men with diagnosed HIV about antiretrovirals reducing infectiousness.

The researchers found that there was a modest relationship between risk assessments and sexual behaviour. Men who reported unprotected anal intercourse with a casual partner tended to perceive sex to be less risky, compared to men who consistently used condoms.

Men who were younger, had less education or who had never tested for HIV also tended to evaluate risks as being less than other men.

This study suggests that information needs to address both gay men’s beliefs about the risks involved in different sexual acts and how these risks might be affected by different levels of viral load.

Sexual health promotion on Facebook

Health promoters wishing to disseminate information on Facebook and other social media need to think carefully about the role such websites play in people’s presentations of themselves to others, according to researchers. Their research was conducted with young people in Australia but has implications for health educators using social media to reach other populations.

Several participants said that it would be “weird” to post sexual health information on Facebook. Their decisions about information shared, comments made, and photos uploaded were not made lightly, but often carefully considered in relation to an imagined audience.

Information which could be read as disclosing something about a young person’s sexual activities or suggesting that he or she had a sexually transmitted infection was seen as highly problematic.

Whereas health professionals may want to use social media to deliver a single take-home message to large numbers of people, users are more likely to share information that they have created, adapted or subverted themselves.

The young people recommended that health promoters use humour in social media interventions. Funny videos were seen as less embarrassing – the viewer is simply enjoying the humour. The participants felt that humorous material was more likely to be disseminated and to be remembered.

Community viral load

In recent years, some researchers have suggested that increases in the uptake of HIV testing and treatment in cities like San Francisco and Vancouver have resulted in a lowering of the average viral load in those places. And they have argued that the average or ‘community’ viral load can explain recent decreases in HIV infections in those cities.

However, now experts have identified some technical problems with community viral load. The experts do not say that viral load and infectiousness is unimportant, but that it is very difficult to measure in a community. Moreover, other factors need to be considered when explaining HIV rates.

One problem is that estimates of community viral load rely on viral load results in people with diagnosed HIV who receive medical care. Undiagnosed people and people who have dropped out of care are likely to have very different viral loads.

Another problem is that the risk of an HIV-negative person acquiring HIV from a new sexual partner depends not only on the average infectiousness of a person with HIV, but also on the likelihood that a new partner has HIV at all. In other words, prevalence needs to be taken into account.

The authors say that it would be more helpful to estimate the proportion of people in the whole population who have detectable HIV. This relies on having a good estimate of the number of people with undiagnosed HIV.

Other recent news headlines

Intimate partner violence associated with subsequent HIV infection in Uganda

Ugandan women who have been subject to violence from a sexual partner are more likely than other women to go on to acquire HIV, according to a large, longitudinal study from the Rakai cohort, published in the May 15 issue of AIDS. Women who had experienced more severe forms of violence, more frequently, or over a longer period of time had greater risks of HIV infection. Read more >>

Higher rates of HIV in US black gay men may be due to smaller choice of partners and more age mixing

Limited partner choice, wider age gaps between partners, and mistaken beliefs about HIV status in regular partners are all driving the substantially higher rates of HIV in US black gay men relative to other ethnicities, a recent study suggests. Read more >>

Combination prevention could "eliminate" HIV transmissions in Vietnam, model projects

A “combination prevention” strategy with targeted HIV testing and early antiretroviral therapy at its core has the potential to virtually eliminate new HIV transmissions in Vietnam, according to a mathematical model published in the online edition of the Journal of Acquired Immune Deficiency Syndromes. The strategy had the biggest impact on transmissions and was most cost-effective when it was targeted at high-risk populations. Read more >>