Summary and highlights of the scientific tracks at the STI & AIDS World Congress 2013,Vienna

The joint meeting of ISSTDR and IUSTI, hosted under the presidency of Professor Angelika Stary in Vienna, concluded by reviewing the six scientific tracks upon which the programme was centred. These presentations were constructed by track chairs and summarised emergent themes across the plenaries, oral sessions and posters.

The Basic Sciences Track was presented by Professor David Lewis who emphasised the concerning findings of Magnus Unemo ¹ (Orebro University Hospital, Sweden, PL01.1) surrounding the global dissemination of extended-spectrum cephalosporin-resistant (ESR) gonococcal superclones. At the University of Health Sciences, Bethesda, Vincent et al. ² (O21.3) proposed that these extensively drug-resistant (XDR) gonococci may have emerged, due to epistatic mutations in the mosaic penA gene.

In Kyoto, some optimism was offered by Unemo’s report that following ceftriaxone therapy (current CDC, WHO and IUSTI standard of care), no ESR gonococci were observed. ¹ The global response to this serious public health challenge remains critical and new treatments are needed.

At the Centre for Microbial Pathogenesis, Ohio, Edwards et al. ³ (SO7.1) investigated the association between adverse pregnancy outcomes and Neisseria gonorrhoeae (GC), using human cell models of disease. GC attachment to primary human amniochorionic epithelial (pace) cells within 90 min using CD11c/CR4 receptors, elicited increased levels of IL-1 β and MMP: linked to preterm labour. ³

Despite discovery over 100 years ago, fascinating research on Treponema pallidum (Tp) continues. Lukehart ⁴ (PL03.3) from the University of Washington, Seattle, discussed Tp’s capacity for evading immunological surveillance as a ‘stealth pathogen’ with complex antigenic variation. An animal model of secondary syphilis demonstrated that chimeric variants derived from seven variable regions were present at different lesion sites. ⁴

At the University of Victoria, Canada, Cameron et al. ⁵ (S07.5) proposed a mechanism whereby Tp activated endothelial cells into a pro-coagulant state for Tp incorporation into the fibrin clot. Subsequent Tp dissemination was contingent on expression of serine protease (Tp0750) and metalloprotease (Tp0751), which degraded fibrin clot stabilisers. ⁵ The utility of quantitative PCR in rapid monitoring of syphilis treatment response was shown by Tipple et al. ⁶ (O05.2), Imperial College, London. Tp DNA was undetectable in all samples by 56 h after treatment with benzathine penicillin. ⁶

The efficacy of RG1-VLP vaccination against 18 high risk and low risk mucosal and cutaneous HPV types was reported by Williamson ⁷ at the University of Cape Town, South Africa (S12.1) and Schellenbacher et al. ⁸ at the Medical University, Vienna (O01.5). The search for a preventative HIV-1 vaccination continues as Morris ⁹ (S12.3) at the National Institute for Communicable Diseases, Johannesburg, reported that efforts to elicit broadly cross-neutralising (BCN) antibodies were unsuccessful, as although antibodies recognised one of four vulnerable sites on the HIV envelope, only 25% of the CAPRISA cohort developed antibodies by three years.

The Clinical Sciences Track was presented by Dr Keith Radcliffe, who highlighted a meta-analysis by Hocking et al., ¹⁰ University of Melbourne (O02.6), which demonstrated the marginally (2.7%) superior efficacy of doxycycline (100 mg twice-daily for seven days) to azithromycin (1 g) for urethral or cervical CT. ¹⁰ However, RCT data are needed to decide the optimal treatment for extragenital CT.

The essential work of development of novel GC therapeutic regimens was presented, with Kirkcaldy ¹¹ (S08.1) at the CDC, Atlanta, demonstrating 100% and 99.5% cure rates for urogenital GC, using azithromycin (2 g PO) with either gentamicin (240 mg IM) or gemifloxacin (320 mg PO), respectively. ¹¹ Extragenital cure rates were 100% with both regimens. ¹¹ At the University of Alabama, Birmingham, Hook et al. ¹² (O02.5) reported a phase two trial showing that solithromycin (1000 or 1200 mg) was well tolerated and 100% effective in eradicating GC.

Jensen ¹³ (S08.4) reviewed the management of Mycoplasma genitalium (MG), one of the most difficult issues currently facing clinicians and associated with 15% of non-gonococcal urethritis (NGU) and 20% of non-chlamydial NGU. As a first-line treatment, doxycycline is unreliable with a 35% eradication rate, while the efficacy of a 1 g single dose versus a five-day course of azithromycin remains uncertain. ¹³ The most reliable second-line treatment against macrolide-resistant MG is moxifloxacin (400 mg, 7–10 days), with nearly 100% cure rate but concern over quinolone resistance is being voiced. ¹³

The long-term reproductive health sequelae for women with both MG and CT were examined by Bjartling et al. ¹⁴ (Malmo, Sweden), who demonstrated that MG was relatively less pathogenic, accounting for 1.6% of pelvic inflammatory disease, compared to 23.6% caused by CT. At the University of Washington, Manhart et al. ¹⁵ (O14.1) assessed the epidemiological connection between bacterial vaginosis and NGU in men, observing that Leptotrichia/Sneathia was significantly associated.

At the San Francisco Department of Public Health, Cohen et al. ¹⁶ (O14.4) found that in 1246 men at the STD clinic, the most frequent factors causing proctitis were GC (14.5%), CT (10.91%), HSV (7.46%), GC and CT co-infection (3.29%) and syphilis (1.2%). ¹⁶ At the University of Melbourne, Bissessor et al. ¹⁷ (O14.6) investigated the causes of infectious proctitis in HIV-positive and HIV-negative men. CT was more common than GC as a cause of proctitis, but both were common in both HIV-positive and HIV-negative men. ¹⁷ HSV (36% versus 19%) and LGV (7.8% versus 0.7%) were significantly more common in HIV positive men than HIV negative men. ¹⁷

Professor Jeanne Marrazzo presented the Epidemiology and Prevention Sciences Track. At the New York City Department of Health and Mental Hygiene, Pathela et al. ¹⁸ (O11.4) observed 2805 men diagnosed with infectious syphilis from 2000 to 2011, who contributed 11,714 person years of follow-up for HIV infection; 423 (15.1%) subsequently acquired HIV with a median time to diagnosis of 582 days. ¹⁸ The 5.42% annual HIV incidence in those aged 13–19 was highlighted. ¹⁸ The concerning evidence that one in 20 MSM with syphilis are subsequently diagnosed with HIV within one year, suggests that frequent HIV testing and pre-exposure prophylaxis (PrEP) should be considered for HIV-negative syphilis cases. ¹⁸

Mugwanya et al. ¹⁹ (O11.2), University of Washington, demonstrated that when part of a comprehensive prevention package, PrEP is not associated with substantial change in risk-taking behaviour in HIV sero-discordant heterosexual relationships.

McGowan ²⁰ (S01.1), University of Pittsburgh, reviewed the history of utilising antiretroviral drugs as PrEP, discussing the search for a topical microbicide. Currently, the FACTS 001 study is evaluating tenofovir gel before and after sex, after the promising findings of the CAPRISA 004 study which showed 39% and 51% reductions in HIV and genital HSV-2, respectively, in women. ²⁰ The tenofovir PrEP-based interventions in the VOICE (MTN-003) study of women in South Africa, Uganda and Zimbabwe have yet to demonstrate an overall effect in preventing HIV-1 acquisition in women but a potential trend in HSV-2 protection may exist, when comparing single interventions (Marazzo et al., ²¹ University of Washington, O11.1). The Ring and ASPIRE studies currently assessing the dapivirine-eluting vaginal ring should report in 2015.

Professor Helen Ward began the summary of the Social and Behavioural Sciences Track by discussing Sevgi Aral’s ²² plenary session on the importance of love, lust and attachment in understanding sexual behaviour and the marginalised ‘stigmatised tail.’

Stenger et al. ²³ (CDC, Atlanta, O12.1) examined a GC ‘risk score’ across 18 social determinants, the most significant being the proportions of population that were ‘non-Hispanic black,’ had ‘households headed by females’ and were ‘vacant housing units.’ In India, Basu et al. ²⁴ (P4.040) observed that drug users were at high levels of sexual risk with poor access to care, while Yadav et al. (P4.041) demonstrated MSM exhibited high levels of alcohol use. ²⁴

Garcia and Ramos ²⁵ (P4.012) addressed critical issues surrounding HIV-related felt stigma, lower condom use and social isolation in MSMs in Brazil, whilst Van Wagoner et al. ²⁶ (O12.2) reported that church attendance in MSM was associated with delayed HIV presentation. Owuar et al. ²⁷ (P4.045) observed that Africans experienced reported stigma in the UK leading to concealment and delayed diagnosis. Young and Champion ²⁸ (P4.033) reported that depressive disorder and substance misuse in Mexican and African Americans were associated with increased risk of STI.

In the United States, Minnis et al. ²⁹ (O12.4) assessed the sexual health intervention ‘Yo Puedo’ in high risk urban areas. Of 162 youth, 66% attended at least one life skills group and a relatively higher proportion of youth who participated, attended a reproductive health clinic follow-up. ²⁹ Ward recommended that before designing treatment interventions, better engagement and acceptability of interventions by participants was necessary.

The Implementation Science Track was presented by Dr Gail Bolan, focusing on two overlying themes of ‘Screening and Treatment,’ and ‘Partner Services.’ Leeuwen et al. ³⁰ assessed the efficiency of CT home collection kits for young people in an Amsterdam STI clinic (O09.5). Using an online intake of 1323 clients <25 years, 78% opted for a home collection kit, 20% requested a STI clinic appointment and 2% preferred a 30-min sexual health consultation with a nurse. ³⁰ Care efficiency improved by using the home collection kits, due to relatively higher CT prevalence which saved 15–30 min of qualified nurse time. ³⁰

At George Washington University, Spielberg et al. ³¹ (O08.4) demonstrated the potential feasibility of online STI testing, with 64% of women preferring home testing for HIV and 61% opting for home delivered STI treatment. A comparative effectiveness trial may be considered, to determine whether an online system can improve the management of bacterial STIs, at a lower cost and higher acceptability than clinic-based services. ³¹ Bernstein et al. ³² (O08.1) found that internet partner services for syphilis and HIV were beneficial, with significantly higher proportions of successfully tested HIV partners and named partners successfully treated for syphilis.

In the Netherlands, Götz et al. ³³ (O08.2) assessed the effectiveness of an internet-based notification system ‘Suggest-A-Test’ (SAT) across 1184 patients at STI clinics in Rotterdam and Amsterdam. SAT users preferred non-anonymous notification, most frequently through SMS. ³³ In total, 14% of partners were notified using SAT, 56% of whom then accessed the site, but only 20% visited the STI clinic. ³³

Barbee et al., ³⁴ University of Washington (O08.3), observed significant provider and patient barriers to bacterial STI screening of HIV positive MSM in primary care, with 28% of patients seeking STI screening elsewhere. At the University of Southampton, Bains et al. ³⁵ (P5.032) observed that in 476 patients across three STI clinics, no patient would have had their treatment delayed and no significant clinical diagnoses would have been missed, by the introduction of an asymptomatic screening pathway for MSM.

The Health Policy and Program Science Track was presented by Dr James Blanchard. Improved understanding of HIV transmission dynamics was highlighted in the systematic review by Shubber et al. ³⁶ (O13.5). Many countries reported that the HIV modes of transmission (MoT) model was under-representing the contribution of female sex workers and their clients, irrespective of the epidemic context. ³⁶ This systematic bias may be secondary to under-estimations of the population sizes.

Prudden et al.’s ³⁷ (O13.2) revised MoT model used more specific subgroups that reduced the estimate of the proportion of the ‘general’ population that were contributing to new infections. By classifying ‘high-risk’ groups into sub-categories such as ‘transactional sex,’ the study yielded a better representation of where new infections were occurring and may provide better guidance for targeting future prevention programmes. ³⁷

The issue of resource allocation for scaling up programmes was addressed. Miller et al.’s ³⁸ (O17.6) analysis of the opt-out HIV testing programme and patterns of testing within a STD clinic in North Carolina, demonstrated that opt-out testing did not affect the already increasing rate of testing. ³⁸ Furthermore, HIV testing rates after the intervention, lead to proportionally less testing of those most at risk. ³⁸ Blanchard emphasised that careful assessment for unintended consequences is needed following the scaling up of new policy.

The RCT’s changing role and use of non-experimental models for impact evaluation was discussed in light of mathematical modelling by Ali et al. ³⁹ (O17.3) for evaluating the HPV vaccination programme in Australia, with substantial reductions in the proportions of women and men (<30 years old) with genital warts.

In closing, Blanchard proposed that the delivery of an intervention should not focus solely on assessing efficacy with a RCT, due to the constraint of maintaining fidelity to a standardised intervention, meaning it cannot identify the complex factors that influence ‘real-world’ effectiveness.

Conflict of interest

The authors declare no conflict of interest.