Category: Viruses

Sexual health of female sex worker in the UK

Female sex workers (FSWs) are assumed to be at increased risk of sexually transmitted infections (STIs). Using routine STI surveillance data, McGrath-Lone et al  in an article published in the latest issue of Sexually Transmitted Infections investigated differences in sexual health between FSWs and other female attendees at sexual health (genitourinary medicine – GUM) clinics in England.

They reported on 2704 FSWs visiting to 131/208 GUM clinics, (primarily large, FSW-specialist centres in London) in 2011. By comparison with other female attendees, FSWs travelled further for their care and had increased risk of certain STIs (eg, gonorrhoea Odds Ratio: 2.76, p<0.001). Significantly migrant FSWs had better sexual health outcomes than UK-born FSWs (eg, period prevalence of chlamydia among those tested: 8.5% vs 13.5%, p<0.001) but were more likely to experience non-STI outcomes (eg, pelvic inflammatory disease OR: 2.92, p<0.001).

They concluded that although FSWs in England have access to high-quality care through the GUM clinic network, there was evidence of geographical inequality in access to these services.

A minority do not appear to access STI/HIV testing through clinics, and some STIs are more prevalent among FSWs than other female attendees.

Targeted interventions aimed at improving uptake of testing in FSWs should be developed, and need to be culturally sensitive to the needs of this predominantly migrant population.

Need and acceptability of human papillomavirus (HPV) vaccination in men

HPV vaccination of young women with the quadrivalent vaccine (HPV4) resulted in a dramatic fall in genital warts and cervical cancer rates. However rolling out a similar vaccination in young men has been hampered by arguments that  male HPV4 vaccination programmes exceed cost-effectiveness thresholds.

Unlike the USA and Australia, European countries do not include men in HPV vaccination programmes, instead focusing on achieving expanded coverage among women to promote herd immunity.

Yet there is  evidence that HPV4 vaccination offers substantial clinical benefits to men and is cost effective among men who have sex with men (MSM). MSM have largely been excluded from mathematical models. A recent study in the journal Sexually Transmitted Infections has shown that HPV related conditions such as anal/genital warts and rectal infections are likely to be profoundly underdiagnosed among MSM in most European cities. The paper concluded that there is an urgent need to improve sexual healthcare tailored to MSM at risk for STIs.

There is also the argument  for a gender-neutral (universal) approach to vaccination.

In the same issue of STI a meta-analysis shows that there are currently a number of obstacles to acceptability of HPV vaccination in  men. They concluded that Public health campaigns should aim to promote positive HPV vaccine attitudes and awareness about HPV risk in men. The paper recommended interventions to promote HPV vaccination for boys and to overcome  obstacles to HPV vaccine acceptability for men.

Human papillomavirus may increase acquisition of HIV

Many sexually transmitted infections (STI) such as herpes and other ulcerative STI’s, chlamydia and gonorrhoea have been known to be associated with increased acquisition of HIV.

A recent meta-analysis in the journal Sexually Transmitted Infections suggests that human papillomavirus (HPV) infections, which is associated with genital warts as well as a number of malignancies, may also be associated with sexual transmission of HIV.

Since HPV is the commonest sexually acquired STI, this association, if confirmed, will have important public health consequences. This is particularly true as most sexually acquired HPV infections can be prevented by  vaccinating children.


HPV and HIV acquisition
HPV and HIV acquisition



HPV vaccination has real population effect on genital warts in Australia

A recent editorial by Simon Barton and Colm O’Mahony in the BMJ highlight real and large declines at the population level of genital warts in both sexes in areas where mass vaccination by the quadrivalent vaccine have been implemented. The authors summarise the achievements to date:

1. A study published by Hammad Ali et al in the same issue reports that survey of of 85 770 new patients from six Australian sexual health clinics show a remarkable reduction in the proportion of women under 21 years of age presenting with genital warts—from 11.5% in 2007 to 0.85% in 2011 (P<0.001). Only 13 cases of genital warts were diagnosed in women under the age of 21 across all six health clinics in 2011. There was no observable effect in women over 30.

2. Interestingly, even though only young women were offered vaccination, there was also a significant decline in genital warts in young men. Between 2007 and 2011 there was a decline of 82% in the prevalence of warts presenting to sexual health clinics in heterosexual men under 21 and 51% in heterosexual men aged 21-30. There were no observed change in prevalence of genital warts in men who have sex with men (MSM). This decline of genital warts in young heterosexual men was thought to be caused to increased herd immunity.

3. Based on these and similar findings and also on grounds of equity the Australian government has begun a publicly funded HPV vaccination program for young men. This aims to reduce the prevalence of genital warts in MSM and also hopefully effect the rising rates of oropharyngeal cancers in men. Ali et al commented that “the vaccination program is expected to increase herd immunity and provide further indirect protection to unvaccinated women” hopefully leading to control, if not elimination of teh targeted HPV types.

4. It is believed that  similar falls in HPV-16 and HPV-18 related cancers – such as cervical, anal and oripharyngeal cancers will be reported in the next few years.

5. The editorial expressed the hope that future vaccines will include other potentially harmful HPV types, such as types 31 and 45.


Non-disclosure of known HIV status in patients visiting a sexually health clinic

Currently in the UK it is estimated that 24%, approximately 22 200 individuals, are unaware of their HIV infection . These data are derived from statistical modelling of many  surveillance, and survey-based data sources. One of the surveillance programmes used is the unlinked anonymous HIV seroprevalence survey, the GUMAnon Survey, where patients who have blood taken at a sexually health clinic would in addition give an additional sample which is tested for HIV after the sample is completely anonymised. The limited information accompanying the sample includes whether the person is known to be HIV positive, has a test in the clinic or refuses an HIV test.

A recent study published in the journal Sexually Transmitted Infections (STI) attempted to identify HIV-infected individuals who attend a genitourinary clinics in the UK aware of their HIV status but fail to tell the clinic they are infected, or on treatment.  In this study in addition to anonymised HIV testing the positive samples had viral load (VL) estimation and after excluding known HIV positives the remaining the samples were analysed for the presence of a panel of antiretroviral drugs.

The authors identified 130 individuals attending a single London sexually transmitted infection clinic in 2009 who refused an HIV test.  Of 28 patients identified by the anonymised test  as being HIV positive who had not admitted to being infected 10 patients underwent a test at the clinic and received a positive test.

The other 18 had  refused an HIV test, although found to be positive by the anonymised test. Thirteen of these (72%, 95% CI: 47% to 90%) had a blood viral load (VL) below detection level  (n=11) or VL <1000 copies/ml (n=2) suggesting they were on antiretroviral treatment. Eight had sufficient blood to undergo antiretroviral testing, and all were positive for the presence of drug; all with therapeutic levels of clinically appropriate combinations.

Thus nearly three quarters of HIV positive patients (72%) who refused an HIV test, and hence would have been considered as not knowing their HIV status, were indeed aware of their status and are on treatment.

These results “presents a number of challenges and dilemmas both for clinics and surveillance systems” says Jackie Cassell, editor of STI journal, who went on to also points out the difficult issues of confidentiality in sexual health services in the age of electronic health records.

HIV treatment of infected partner reduces transmission in heterosexual couples

Based on results of randomised clinical trials the World Health Organization recommends antiretroviral drugs for all HIV infected adults in serodiscordant heterosexual relationships at all stages of the disease. But does this strategy work in real life situations?

A recent study published in the Lancet has for the first time reported that such a public health approach is feasible and the outcomes are sustainable at a large scale and in a developing country setting.

New analyses from China look encouraging, say researchers. Between 2003 and 2011, uninfected partners of treated people were significantly less likely to seroconvert than uninfected partners of untreated people (1.3 infections/100 person years (95% CI 1.2 to 1.3) v 2.6 (2.4 to 2.8)). After adjustments, treatment of infected partners was associated with a 26% reduction in risk of transmission to uninfected partners (hazard ratio 0.74, 0.65 to 0.84).

The analyses compared around 24 000 treated couples with nearly 15 000 untreated couples registered in China’s national HIV epidemiology database.

It is hard to say whether treatment was entirely responsible for reducing transmission, because people who were treated were older, sicker, and may have had less sex, or less risky sex, than those who were not yet treated, says a linked comment by the Lancet

But the findings hint at a direct effect. Treated couples looked better protected, despite the relatively low CD4 counts (and presumably higher viral loads) necessary for treatment in China.

Treatment was associated with lower transmission when HIV had been acquired from a transfusion of blood products (50% of the treated couples) or heterosexual sex, but not when it had been acquired from injecting drugs.

Lancet issue on the state of global health

The Lancet has devoted an entire issue to various aspects of global health. The issue is available free for download.

An edited extract from the executive summary follows:

The Global Burden of Disease Study 2010 (GBD 2010) is the largest ever systematic effort to describe the global distribution and causes of a wide array of major diseases, injuries, and health risk factors.

The results show that infectious diseases, maternal and child illness, and malnutrition now cause fewer deaths and less illness than they did twenty years ago. As a result, fewer children are dying every year, but more young and middle-aged adults are dying and suffering from disease and injury.

Thus non-communicable diseases, such as cancer and heart disease, become the dominant causes of death and disability worldwide.

Since 1970, men and women worldwide have gained slightly more than ten years of life expectancy overall, but they spend more years living with injury and illness.


New HIV infection in UK in men who have sex with men exceeds heterosexual transmission after many years

Annual report of HIV infections in the United Kingdom in 2001 published by Health Protection Agency (HPA) show that for the first time in  many years newly diagnosed infections were higher in men who have sex with men (MSM) than transmission through heterosexual intercourse.

By the end of 2011, there were an estimated 96,000 (95% credible interval 90,800 – 102,500) people were living with HIV in the UK. Approximately one quarter (22,600, 24% [19%- 28%]) of these were undiagnosed and unaware of their infection. Fig 1

Fig 1. People infected with HIV at the end of 2011


This is an increase from the 91,500 people estimated to have been living with HIV by the end of 2010. The estimated prevalence of HIV in 2011 was 1.5 per 1,000 (1.5-1.6) population of all ages, 2.1 per 1,000 (1.9 – 2.3) men and 1.0 per 1,000 (1.0 – 1.1) women.

The rise in new diagnosis in MSM (Fig 2) is particularly worrying as nearly half the patients (47%) are diagnosed late when their immune system is already compromised increasing the chance of a fatal outcome within one year of diagnosis ten fold. These deaths are totally avoidable with the use of anti-viral therapy early in the infection.


Fig 2. New cases of HIV by exposure category


Pre-exposure prophylaxis can be a cost effective addition to other preventative options for men who have sex with men

HIV pre-exposure prophylaxis (PrEP), the use of antiretroviral drugs by uninfected individuals to prevent HIV infection, has demonstrated effectiveness in preventing acquisition in a high-risk population of men who have sex with men (MSM).

Researchers from the Imperial College London have developed a mathematical model representing the HIV epidemic among MSM and transwomen (male-to-female transgender individuals) in Lima, Peru, to investigate how PrEP can be used cost-effectively to prevent HIV infection in such populations.

The study reported that strategic PrEP intervention could be a cost-effective addition to existing HIV prevention strategies for MSM populations.

However, PrEP will not arrest HIV transmission in isolation because of its incomplete effectiveness and dependence on adherence, and because the high cost of programmes limits the coverage levels that could potentially be attained.