Posts in ‘Transmission of STI’ category

Is antiretroviral treatment for HIV increasing the susceptibility to syphilis

Posted on 9th August 2017 by · No comments

Recently, the world has experienced a rapidly escalating outbreak of infectious syphilis primarily affecting men who have sex with men (MSM); many are taking highly active antiretroviral therapy (ARV) for HIV-1 infection.

Treatment with ARV reduces risk of infection (because of greatly reduced viral load) and near-normal life expectancy for those on treatment. The currently accepted hypothesis is that these factors result in increased sexual risk-taking, especially unprotected anal intercourse, leading to more non-HIV-1 sexually transmitted infections, including gonorrhoea, chlamydia and syphilis.

However, syphilis incidence has increased more rapidly than other STDs. In a recent open access article in the journal Sexually Transmitted Infections, Reckart and colleagues hypothesise that ART itself  may alter the innate and acquired immune responses to Treponema pallidum, the bacterium causing infectious syphilis, and that this biological explanation plays an important role in the current syphilis epidemic.

In a leading article in the same journal, Susan Tuddenham and colleagues (only available to subscribers), find the hypothesis intriguing despite some flaws. They go on to suggest that further work is necessary to look at the mechanisms underlying the current syphilis epidemic.

In the same issue David Glidden et al point out that in the early double blind trials with pre-exposure prophylaxis (PrEP) no increase in syphilis was found between those taking PrEP and those taking placebo. These findings would suggest that short term exposure to ART has no effect on the acquired immune responses to Treponema pallidum.

Sexually transmitted infections: challenges ahead

Posted on 21st July 2017 by · No comments

A commissioned article in Lancet Infectious Diseases on July 9, 2017 highlights some of the major issues and challenges facing us in the growing global epidemic of sexually transmitted infections (STI). Authors Prof Mabhus Unemo et al summarise the key issues as follows:

WHO estimated that nearly 1 million people become infected every day with any of four curable sexually transmitted infections (STIs): chlamydia, gonorrhoea, syphilis, and trichomoniasis. Despite their high global incidence, STIs remain a neglected area of research.

In this Commission, we have prioritised five areas that represent particular challenges in STI treatment and control.

Chlamydia remains the most commonly diagnosed bacterial STI in high-income countries despite widespread testing recommendations, sensitive and specific non-invasive testing techniques, and cheap effective therapy. We discuss the challenges for chlamydia control and evidence to support a shift from the current focus on infection-based screening to improved management of diagnosed cases and of chlamydial morbidity, such as pelvic inflammatory disease.

The emergence and spread of antimicrobial resistance in Neisseria gonorrhoeae is globally recognised. We review current and potential future control and treatment strategies, with a focus on novel antimicrobials.

Bacterial vaginosis is the most common vaginal disorder in women, but current treatments are associated with frequent recurrence. Recurrence after treatment might relate to evidence that suggests sexual transmission is integral to the pathogenesis of bacterial vaginosis, which has substantial implications for the development of effective management approaches.

STIs disproportionately affect low-income and middle-income countries. We review strategies for case management, focusing on point-of-care tests that hold considerable potential for improving STI control.

Lastly, STIs in men who have sex with men have increased since the late 1990s. We discuss the contribution of new biomedical HIV prevention strategies and risk compensation.

Overall, this Commission aims to enhance the understanding of some of the key challenges facing the field of STIs, and outlines new approaches to improve the clinical management of STIs and public health.

Read full article on Lancet Infectious Diseases

Sexually abused children should be offered HPV vaccination

Posted on 19th November 2015 by · No comments

Should children exposed to sexual abuse be offered human papillomavirus (HPV) vaccination alongside screening for sexually transmitted infections? A recent article in the Lancet argues for a yes answer.

The WHO defines childhood sexual abuse  as the involvement in sexual activity of a child under the age of 18 years who did not give informed consent or is not developmentally prepared.

The global prevalence of childhood sexual abuse is estimated to be 8–31% for girls and 3–17% for boys. The true figures are probably nearer the upper figure.

According to a review, parents were the perpetrators of about 45% of cases of childhood sexual abuse in the USA, and other relatives were responsible for a further 19%.  Others included figures of authority such as priests and teachers. Survivors of such abuse are often hesitant to report such incidents because of shame and fear of retribution. Thus, the incidence and prevalence of childhood sexual abuse is almost certainly underestimated. Read the rest of this post »

Daily pri-exposure prophylaxis (PrEP) prevents HIV infection in high risk gay men

Posted on 23rd September 2015 by · No comments

Daily HIV medicine taken by men who have sex with men (MSM) reduces risk of HIV infection by 86% as was reported by Molina J-M, and colleagues in the ANRS Ipergay trial  at the Conference on Retroviruses and Opportunistic Infections held in Seattle, USA in 2015 (23LB.).

Molina et al reported the final results of a three year study which randomised MSM who were negative for HIV to either take daily HIV prophylaxis with two anti-retroviral drugs in a single tablet immediately or deferred for 1 year.

The study showed that those taking the drugs on a daily basis have a 86% reduction in the risk of being infected by HIV than MSM not taking the drug (p=0.0001). The trial was stopped in October of 2014 and all participants in the  deferred group were offered pre-exposure prophylaxis (PrEP)

As a Lancet editorial commented:

The science is now clear: oral pre-exposure prophylaxis (PrEP) with a coformulation of tenofovir disoproxil fumarate and emtricitabine (Truvada) significantly reduces the risk of HIV infection among individuals at high risk of HIV infection.

The news that PrEP has shown consistent efficacy among those who take it as prescribed should be a cause for celebration, and galvanise action to ensure access to PrEP for those who could benefit the most. But almost 3 years since the US Food and Drug Administration approved tenofovir–emtricitabine for PrEP little is being done on implementation.

With more than 2 million new HIV infections every year worldwide, it is time for that to change.

Transmitting an STI and the law

Posted on 31st July 2014 by · No comments

On May 8 2014 the UK Court of Appeal dismissed the appeal of David Golding against a 14 month prison sentence for transmitting herpes to his partner.

An Editorial in the BMJ by Emily Clarke an colleagues highlights the numerous and  complicated issues that arise from this verdict including:

what constitutes grievous bodily harm,

how you determine that sexual transmission has occurred,

how serious is herpes infection, and

what this judgement means both for health care workers who advise and inform patients on the risks of transmission and on the infected individual and their duty of informing all partners of potential risk of transmitting an infection even during asymptomatic shedding.

The Editorial correctly highlights the dangers of criminalizing sexually transmitted infections and the various problems that arise from this judgement which was based on a law passed 170 years ago addressing totally unrelated issues and at a time when STI’s were not understood as they are today.

Human rights violations against sex workers: burden and effect on HIV

Posted on 31st July 2014 by · No comments

This is part of a series of articles on HIV and sex workers published by The Lancet and freely available.

In this article Michelle Decker et al  reviewed evidence from more than 800 studies and reported on the burden and HIV implications of human rights violations against sex workers.

Abuses of human rights are  perpetrated by both state and non-state actors. Such violations directly and indirectly increase HIV susceptibility, and undermine effective HIV-prevention and intervention efforts.

Violations include homicide; physical and sexual violence, from law enforcement, clients, and intimate partners; unlawful arrest and detention; discrimination in accessing health services; and forced HIV testing.

Abuses occur across all policy regimes, although most profoundly where sex work is criminalised through punitive law.

The authors conclude that protection of sex workers is essential to respect, protect, and meet their human rights, and to improve their health and wellbeing.

Research findings affirm the value of rights-based HIV responses for sex workers, and underscore the obligation of states to uphold the rights of this marginalised population.

Bacteria living in men’s penises could be promoting sexually transmitted infections

Posted on 9th July 2014 by · No comments

The debate about whether to circumcise or not continues to raise passions. The fact that male circumcision reduces acquisition of HIV from an infected partner has been proven by three randomised clinical trials. And male circumcision may also protect against other sexually transmitted infections.

One of the most powerful arguments against male circumcision is that it only addresses acquired infections in the male. A recent report in the Scientist that bacteria living under the foreskin can promote STI’s would help answer this critique.

Just as the vaginal microbiome differs among women and changes over time, the penis is home to a variety of bacteria that vary with age, sexual activities, and whether the man is circumcised, among other things. And it’s not just the skin that envelops the male sexual organ that’s inhabited by microbes: researchers continue to identify bacteria that dwell within the urogenital tract, a site once considered sterile in the absence of infection.

David Nelson and colleagues at Indiana University in Bloomington found evidence to suggest that the sexually transmitted pathogens in the urogenital tract were obtaining metabolites from other microbes. “There was a signature in the chlamydial genome that suggested this organism might be interacting with other microorganisms,” said Nelson. “That’s what initially piqued our interest. And when we went in and started to look, we found that there were a lot more [microbes] than we would have anticipated being there.”

The researchers found that some men pass urine containing a variety of lactobacilli and streptococci species, whereas others have more anaerobes, like Prevotella and Fusobacterium. In terms of overall composition, “we see a lot of parallels to the gut,” said Nelson, noting that there doesn’t seem to be a standout formula for a “healthy” urogenital tract. Commensal microbes within the urethra could make a man more susceptible to infection by supporting colonization by pathogens like Chlamydia, whereas bacteria that consume the environment’s nutrients could help prevent it. “We just don’t know at this point,” said Nelson.

To date, circumcision is the known largest influence on the composition of the penis microbiome. In a 2010 PLOS ONE paper, Lance Price of the Translational Genomics Research Institute in Phoenix, Arizona, and his colleagues showed that the bacteria that colonized the base of the penis’s tip, or glans, varied before and after circumcision. More specifically, the researchers found fewer anaerobic bacteria within six months after the men in a study were circumcised. Those findings have since been confirmed.

Definitely further studies in this field should be encouraged.