How effective are condoms in anal sex – really?
It is important to stress that this is an effectiveness study: it looks at the overall effect in preventing HIV of 100% condom use as a safer-sex strategy in gay men.
Condom efficacy – to what extent they prevent HIV infection when used correctly, as well as consistently – is likely to be higher than that 70%, as effectiveness studies rely on self-report (what people say happens) and will include occasions when condoms slip off, break, leak or, despite best intentions, are not used.
The study was conducted by the US Centers for Disease Control (CDC) and presented to the 20th Conference on Retroviruses and Opportunistic Infections (CROI 2013). It looked at HIV infection rates in 3490 initially HIV-negative gay men who said they had had at least one experience of anal sex with an HIV-positive partner. The men were categorised according to whether they said they always, sometimes or never used condoms.
The overall reduction in the likelihood of HIV infection in men who always used condoms during either receptive or insertive anal intercourse was 70%. The study analysed data from two very different studies, and in the one that provided a safer-sex support programme, it was 86%, compared with under 60% in the other.
The 70% effectiveness rate was the same as that found in the only previous study of condom effectiveness in anal sex, which was conducted in 1989.
The CDC study also found that ‘sometimes’ using condoms was no more effective than 'never' using them. This may sound unlikely, but researcher Dawn Smith commented that each time a condom is not used, it degrades the overall effectiveness of condom use. This means that even when people use condoms sometimes, if they also have many episodes of unprotected sex, it may end up amounting to no protection. The CDC will now look at what level of condom use remains protective.
It also found that 100% condom use is hard to maintain in the long run: while two-thirds of men in the study (including those who had not had HIV-positive partners) maintained condom use for at least one six-month period, only one in six managed it over the three to four years of the studies analysed.
Comment: While this study’s results may surprise people who assume condoms are more effective, it doesn’t actually tell us much we did not know already. It shows that ‘safer sex’, as traditionally formulated, is hard to maintain in the long run, and adds to the case that alternative prevention methods that supplement condom use are badly needed for gay men.
Why did PrEP and microbicides not work for African women?
The VOICE trial randomised over 5000 women from South Africa, Zimbabwe and Uganda to take a daily tenofovir pill or a tenofovir/FTC (Truvada) pill as PrEP or to use a tenofovir-containing gel as a microbicide in advance of sex. It compared infection rates in these women and infection rates in women given a placebo (a dummy pill or gel).
But delegates at CROI 2013 heard that all three methods had proved no better than placebo as the overall infection rate was statistically the same in all arms of the trial.
The most striking result was that, while the women in the study said they had used the pill or gel 90% of the time, analysis of drug levels in blood and vaginal fluids showed that just over a quarter of women had taken a pill in the previous 48 hours and under a quarter had used the gel. Fewer than half the women showed signs of using the study medication at any point during the trial. Despite this, nine out of ten women stayed in the trial and attended appointments.
Women who were married were 2.6 times more likely to use the study medication, and they were very much less likely to become infected with HIV – less than 1% a year compared with 7% of unmarried women. Older women (over 25) were also half as likely to become infected as younger women.
These results replicate those from one PrEP study but contrast with those from another: in FEM-PrEP, a study largely in young single women, PrEP was ineffective, whereas in Partners PrEP (a study involving couples) it had 67% efficacy in women – and drug level studies showed near-100% adherence rates.
Comment: The high retention rates seen in this trial suggest that the benefits of joining such a trial in a resource-poor setting are large – maybe so large as to make the disclosure of non-adherence very difficult for participants. A supportive relationship clearly helps adherence, but it is those without one who have the highest HIV incidence and need something like PrEP most urgently. The researchers called for research “to determine which populations might benefit” from PrEP, but it is perhaps better to aim research at seeing what kind of PrEP might work for the most vulnerable. Forthcoming qualitative research from VOICE may uncover women’s reasons for non-adherence.
US gay young people find taking PrEP hard, too
The young men's mobility appeared to be the largest reason for poor PrEP adherence, with 60% reporting 'being away from home' as a reason they did not take their pills.
Only 17% of those initially assessed as being eligible attended a screening appointment because of limited staffing levels. This led to long wait times for eligible participants and thus loss to follow-up when staff tried to contact them. Once young people were enrolled in the study, however, retention was high: 98.5% consistently attended appointments.
Twice as many participants who expressed an opinion said they did not like the idea of having to take a pill every day compared to those who said they liked it. In contrast, the large majority of participants liked taking part in the study as a whole, appreciated the regular health and behavioural monitoring at study visits, and valued having safer-sex counselling.
Comment: It’s remarkable how similar the results of this small study of young gay men are to the VOICE study described above. The young men in this study clearly valued its social benefits but needed more support to use PrEP effectively. Participants' contact details kept changing, and being away from home was the most common reason cited for both poor recruitment and non-adherence; this study suggests that attention given to convenient, ‘portable’ drug formulations and ways of carrying pills that do not threaten disclosure may help. It’s also worth commenting that what makes taking PrEP difficult for young people also applies to HIV treatment.
Majority with HIV ‘undetectable’ in France, UK – and sometimes in the US
The proportion of people with HIV who have an undetectable viral load and are therefore much less likely to be infectious is crucial to the success of programmes that aim to bring down HIV infections by putting more people on treatment.
Last year, research from the UK Health Protection Agency (HPA) showed that 53% of gay men living with HIV in the UK were on antiretroviral therapy (ART) and had an undetectable viral load, compared with 56% of French gay men. Preliminary UK data show that the proportion of people with an undetectable viral load in other groups is similar.
There are slight differences between France and the UK: more gay men on ART in the UK have undetectable viral loads; conversely, in the UK an estimated 26% of HIV positive gay men remain undiagnosed, but only 17% in France.
Other research suggests that previous estimates of the proportion of people with HIV in the US who are on ART with an undetectable viral load may have been too low and may in some areas be closer to European figures.
Estimates by the US CDC presented last year show that only a quarter of people with HIV in the US might have a viral load below 50 copies/ml. While the US has the same rates of diagnosis and viral suppression as Europe, it appeared from the research that far fewer people remained in medical care after diagnosis.
Now data from New York and from the health insurers Kaiser Permanente suggest that there are actually more people taking ART than there are listed as being in medical care.
A study from Seattle found that one in five of those listed as not being in medical care were in fact in care: half of them had moved out of area while the other half had attended appointments but not had CD4 counts or viral load tests done, which are used as indicators of care. Once this was taken into account, viral suppression rates in Seattle were similar to those in the European studies.
Comment: While the prevention benefits of ART are seen as crucial to making a serious reduction to the HIV epidemic in many countries, these studies show that measuring the epidemiological effect of ART is complex, especially in countries with non-centralised health systems and surveillance. They also underline how addressing health inequalities may make a crucial difference to whether ART works as prevention.
Scientists study possible four-times-a-year anti-HIV drug
An injectable, long-lasting integrase inhibitor drug, when given to rhesus monkeys exposed to a version of HIV, completely protected them against viral infection via the rectum. This drug, GSK744, has already been given as a single dose to HIV-negative human volunteers, and has a half-life of 21 to 50 days. This means that if it proves safe and effective in humans, it could be given as an injection as infrequently as four times a year, though individual variations seen in this study mean that monthly or two-monthly dosing might be safer.
None of the monkeys given GSK744 became infected or have shown any sign of virus in their blood. The drug is similar to dolutegravir, already nearing approval as an anti-HIV drug in Europe and the US.
Levels of GSK744 seen in monkeys’ rectal tissues were equivalent to a level that would be expected to be protective in humans.
In another study, monkeys given a vaginal ring impregnated with the drug tenofovir were protected against infection. While human research into vaginal rings is already well advanced, this is the first time an experiment has shown they may be effective against repeated vaginal exposure.
Comment: Given that adherence is turning out to be a major barrier to the effectiveness of pre-exposure prophylaxis – see the reports on PrEP trials above – HIV drugs given by injection at quarterly sexual health check-ups could, in the long term, be a more feasible way of offering biomedical protection against HIV. The researchers are studying the protected monkeys to see if there is any sign of virus in their systems and to determine the minimum effective dose.
Many people in the UK don’t disclose HIV at sexual health check-ups
Investigators at the John Hunter Clinic in London identified 18 HIV-positive blood samples obtained from people who had a sexually transmitted infection (STI) check-up, were not known to have HIV, did not test for it, and left with an apparently undiagnosed HIV infection. Viral load monitoring and testing for the presence of anti-HIV drugs allowed the investigators to see if the patients were actually aware of their infection. Thirteen of the samples had an undetectable or very low viral load and all eight of those tested for the presence of antiretroviral drugs (ARVs) were positive with drugs present at therapeutic levels. A previous study, presented to the British HIV Association conference in 2011, came to similar conclusions.
Comment: Seventy per cent of people offered an HIV test during UK STI checkups now accept (83% of gay men). Nonetheless, there has been worrying evidence for some time that some of the minority of people who refuse are also amongst those at highest risk of HIV, and it has been uncertain whether they are avoiding testing out of anxiety or are in fact already HIV positive and choosing not to disclose it. The discovery that over half of such cases may be people already diagnosed with HIV is good news, in a way, as it could mean that current estimates of the prevalence of undiagnosed HIV infections in the UK are too high. However, because of non-disclosure, people with HIV may not be receiving appropriate care when using sexual health services.
European HIV prevention webinars – treatment as prevention
As part of its European HIV prevention work, NAM is collaborating with AVAC to provide a series of webinars (conference calls with accompanying slides) to train and inform prevention advocates and anyone interested in the newest developments in HIV prevention technology.
The third webinar is entitled:
Treatment as prevention – evidence from Europe and beyond
This 90-minute webinar will examine treatment as prevention, the influence of treatment guidelines and whether antiretroviral therapy is starting to curb the HIV epidemic in Europe. The presentations will be followed by a question and answer session with our expert speakers. The webinar will be conducted in English.
Time and date: 2pm UK time (GMT), Thursday 28 March (3pm CET)
To register for the webinar and get phone numbers and joining instructions click this link: https://cc.readytalk.com/r/nk4cee12jyad
The webinar will feature presentations by Dr Valerie Delpech from the UK’s Health Protection agency, Virginie Supervie from the French Health Research Agency INSERM, Brian West, chair of the European AIDS Treatment Group, and Gus Cairns, from NAM.
European advocates interested in learning more about HIV treatment as prevention are encouraged to join this webinar and to email questions in advance to gus@nam.org.uk. During the event, participants will be encouraged to ask questions via telephone.
Other recent news headlines
Menstrual cycle affects women’s viral load
A Thai study has found that women’s HIV viral load in vaginal fluids varies nearly sixfold during their menstrual cycle, being highest around the time of their period and lowest at ovulation. The researchers estimated that this could represent a 65% difference in the risk of female-to-male transmission.
HIV treatment prevents hepatitis B
Use of antiretroviral therapy that includes drugs active against both hepatitis B virus and HIV reduces the risk that people living with HIV will become infected with hepatitis B – in effect acting as pre-exposure prophylaxis for hepatitis B. A study from Amsterdam’s largest HIV clinic has found that. since 2002, new hepatitis B infection has become six times less common than hepatitis C infection, and is less common in people taking tenofovir and/or 3TC or FTC.
Early treatment may lead to 15% of people controlling HIV without drugs
A study from France has found that starting antiretroviral therapy (ART) within ten weeks of HIV infection, and continuing it for at least two years, results in a relatively high proportion of people being able to control HIV when subsequently off treatment. It found that 15.3% maintained an undetectable viral load for at least two years afterwards and that the average time spent off treatment without a significant rise in viral load in a set of 14 patients studied more closely was seven years, with some still off therapy.
Editors' picks from other sources
England: Sexual health improvement framework published
from Department of Health
A Framework for Sexual Health Improvement in England sets out the government’s ambitions for improving sexual health and, amongst other things, recommends an increase in the number of people in high-risk groups being tested for HIV.
Germany: National AIDS Council releases powerful policy statement on HIV criminalisation
from HIV Justice Network
The German National AIDS Council – an independent advisory body of the Ministry of Health consisting of experts from the fields of research, medical care, public health services, ethics, law, social sciences, as well as people from civil society – has produced a consensus statement on HIV criminalisation during consensual sex. The statement says that "Attributing either partner as perpetrator or victim is not appropriate" and that "Criminal proceedings regarding the transmission of HIV from consensual sexual intercourse do not contribute to HIV prevention".
Changing my mind on treatment as prevention
from Positive Lite
Bob Leahy, editor of Canadian HIV magazine website Positive Lite, used to be a strong opponent of treatment as prevention. But times change and there has been a sea change in his view.
Bee Venom Destroys HIV And Spares Surrounding Cells
from HIV / AIDS News From Medical News Today
Nanoparticles containing the bee venom toxin melittin can destroy HIV while at the same time leaving surrounding cells unharmed, scientists from Washington University School of Medicine have found. The bee-venom nanoparticle suspension is a promising candidate for a microbicide.