Modelling the contribution that different sexual practices involving the oropharynx and saliva have on Neisseria gonorrhoeae infections at multiple anatomical sites in men who have sex with men.

BACKGROUND: The spectrum of sexual practices that transmit Neisseria gonorrhoeae in men who have sex with men (MSM) is controversial. No studies have modelled potential Neisseria gonorrhoeae transmission when one sexual practice follows another in the same sexual encounter ('sequential sexual practices'). Our aim was to test what sequential practices were necessary to replicate the high proportion of MSM who have more than one anatomical site infected with gonorrhoea ('multisite infection'). METHODS: To test our aim, we developed eight compartmental models. We first used a baseline model (model 1) that included no sequential sexual practices. We then added three possible sequential transmission routes to model 1: (1) oral sex followed by anal sex (or vice versa) (model 2); (2) using saliva as a lubricant for penile-anal sex (model 3) and (3) oral sex followed by oral-anal sex (rimming) or vice versa (model 4). The next four models (models 5-8) used combinations of the three transmission routes. RESULTS: The baseline model could only replicate infection at the single anatomical site and underestimated multisite infection. When we added the three transmission routes to the baseline model, oral sex, followed by anal sex or vice versa, could replicate the prevalence of multisite infection. The other two transmission routes alone or together could not replicate multisite infection without the inclusion of oral sex followed by anal sex or vice versa. CONCLUSIONS: Our gonorrhoea model suggests sexual practices that involve oral followed by anal sex (or vice versa) may be important for explaining the high proportion of multisite infection.

Cost-effectiveness of two screening strategies for Chlamydia trachomatis and Neisseria gonorrhoeae as part of the PrEP programme in the Netherlands: a modelling study.

OBJECTIVES: Pre-exposure prophylaxis (PrEP) users are routinely tested four times a year (3 monthly) for asymptomatic Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) infections on three anatomical locations. Given the high costs of this testing to the PrEP programme, we assessed the impact of 3 monthly screening(current practice), compared with 6 monthly on the disease burden. We quantified the difference in impact of these two testing frequencies on the prevalence of CT and NG among all men who have sex with men (MSM) who are at risk of an STI, and explored the cost-effectiveness of 3-monthly screening compared with a baseline scenario of 6-monthly screening. METHODS: A dynamic infection model was developed to simulate the transmission of CT and NG among sexually active MSM (6500 MSM on PrEP and 29 531 MSM not on PrEP), and the impact of two different test frequencies over a 10-year period. The difference in number of averted infections was used to calculate incremental costs and quality-adjusted life-years (QALY) as well as an incremental cost-effectiveness ratio (ICER) from a societal perspective. RESULTS: Compared with 6-monthly screening, 3-monthly screening of PrEP users for CT and NG cost an additional €46.8 million over a period of 10 years. Both screening frequencies would significantly reduce the prevalence of CT and NG, but 3-monthly screening would avert and extra ~18 250 CT and NG infections compared with 6-monthly screening, resulting in a gain of ~81 QALYs. The corresponding ICER was ~€430 000 per QALY gained, which exceeded the cost-effectiveness threshold of €20 000 per QALY. CONCLUSIONS: Three-monthly screening for CT and NG among MSM on PrEP is not cost-effective compared with 6-monthly screening. The ICER becomes more favourable when a smaller fraction of all MSM at risk for an STI are screened. Reducing the screening frequency could be considered when the PrEP programme is established and the prevalence of CT and NG decline.

Adaptive guidelines for the treatment of gonorrhea to increase the effective life span of antibiotics among men who have sex with men in the United States: A mathematical modeling study.

BACKGROUND: The rise of gonococcal antimicrobial resistance highlights the need for strategies that extend the clinically useful life span of antibiotics. Because there is limited evidence to support the current practice of switching empiric first-line antibiotic when resistance exceeds 5% in the population, our objective was to compare the impact of alternative strategies on the effective life spans of antibiotics and the overall burden of gonorrhea. METHODS AND FINDINGS: We developed and calibrated a mathematical model of gonorrhea transmission among men who have sex with men (MSM) in the United States. We calibrated the model to the estimated prevalence of gonorrhea, the rate of gonorrhea cases, and the proportion of cases presenting symptoms among MSM in the US. We used this model to project the effective life span of antibiotics and the number of gonorrhea cases expected under current and alternative surveillance strategies over a 50-year simulation period. We demonstrate that compared to the current practice, a strategy that uses quarterly (as opposed to yearly) surveillance estimates and incorporates both the estimated prevalence of resistance and the trend in the prevalence of resistance to determine treatment guidelines could extend the effective life span of antibiotics by 0.83 years. This is equivalent to successfully treating an additional 80.1 (95% uncertainty interval: [47.7, 111.9]) gonorrhea cases per 100,000 MSM population each year with the first-line antibiotics without worsening the burden of gonorrhea. If the annual number of isolates tested for drug susceptibility is doubled, this strategy could increase the effective life span of antibiotics by 0.94 years, which is equivalent to successfully treating an additional 91.1 (54.3, 127.3) gonorrhea cases per 100,000 MSM population each year without increasing the incidence of gonorrhea. Study limitations include that our conclusions might not be generalizable to other settings because our model describes the transmission of gonorrhea among the US MSM population, and, to better capture uncertainty in the characteristics of current and future antibiotics, we chose to model hypothetical drugs with characteristics similar to the antibiotics commonly used in gonorrhea treatment. CONCLUSIONS: Our results suggest that use of data from surveillance programs could be expanded to prolong the clinical effectiveness of antibiotics without increasing the burden of the disease. This highlights the importance of maintaining effective surveillance systems and the engagement of policy makers to turn surveillance findings into timely and effective decisions.

High-resolution melting analysis for rapid detection of the internationally spreading ceftriaxone-resistant Neisseria gonorrhoeae FC428 clone.

OBJECTIVES: Increased awareness of the international spread of the ceftriaxone-resistant Neisseria gonorrhoeae FC428 clone, which threatens recommended dual therapy, is essential. The objective of the present study was to develop and evaluate a rapid, simple and cost-effective method based on high-resolution melting (HRM) analysis for direct detection of the FC428 clone from clinical isolates and specimens. METHODS: The singleplex HRM assay was designed to identify the FC428 clone by using specific primers, which flank the alteration A311V in the penA-60.001 allele. Analytical performance was initially evaluated by testing 623 isolates and a panel of non-gonococcal strains. To ensure the method can be directly applied in clinical samples, two internal control targets (opa and porA) were also designed and included in the final multiplex HRM assay. Two hundred and eighty-two clinical samples (94 urine and 188 urethral/genital swabs) were then analysed using this multiplex HRM assay. RESULTS: The FC428 clone was easily differentiated from the non-mosaic alleles and other mosaic alleles without A311 mutations by comparing the differences in melt curves. Cross-reactivity was not observed for the penA-60.001 allele when testing 15 non-gonococcal Neisseria strains. When applied to the 623 isolates, the HRM assay successfully characterized one isolate as an FC428 clone (MLST1903, NG-MAST3435, NG-STAR233). Our data show that the multiplex HRM assay with high specificity can be directly applied in clinical samples. CONCLUSIONS: This method can generate results within 90 min at a cost of less than US$0.5 per isolate or sample, making this assay an ideal tool for large epidemiological studies to enhance surveillance of the internationally transmitted ceftriaxone-resistant N. gonorrhoeae FC428 clone.

Healthcare providers and community perspectives on expedited partner therapy (EPT) for use with gay, bisexual and other men who have sex with men.

OBJECTIVES: Expedited partner therapy (EPT) is an effective strategy to reduce rates of chlamydia and gonorrhoea infection and ensure sexual partners are treated. Currently, EPT is provided to heterosexual patients; however, EPT is not routinely recommended for use with gay, bisexual and other men who have sex with men (GBMSM) because of concerns about HIV coinfection. The objective of the qualitative study was to understand provider and community views on the use of EPT with GBMSM. METHODS: Using convenience sampling methods, we recruited a sample of 18 healthcare providers and 21 GBMSM to participate in in-depth, semistructured interviews. Interviews were conducted over the phone and included questions about knowledge, experiences and potential barriers and facilitators to the use of EPT with GBMSM. RESULTS: Most providers wanted to provide EPT to GBMSM and believed that the potential barriers and concerns to EPT use were not unique to a patient's sexual orientation. Several providers noted that they were currently providing EPT to GBMSM as part of HIV prevention services. Community members were generally unaware of EPT as a service and most indicated that they would only use EPT if they were in a committed relationship. Barriers included partner allergies and resistance, pharmacy protocols, structural concerns (eg, insurance coverage, pharmacists onsite and transportation) and potential disclosure issues. Facilitators included cultural humility and telemedicine with patients' partners to overcome these barriers. CONCLUSIONS: Acceptability of EPT use for both chlamydia and gonorrhoea was high among providers and community members. Barriers to EPT use, including concerns about patients' partners' allergies and resistance, disclosure concerns and linkage to HIV prevention services can be overcome through cultural humility trainings and telemedicine. Changing EPT recommendations at the national level to be inclusive of GBMSM is critical to curtail the rising STI and HIV epidemic.

Impact of frequent testing on the transmission of HIV and N. gonorrhoeae among men who have sex with men: a mathematical modelling study.

OBJECTIVES: To investigate the impact and efficiency of combined testing for HIV and other STIs on HIV and STI transmission among men who have sex with men (MSM) and to assess what subgroups of MSM should be targeted for frequent testing. METHODS: We developed an agent-based transmission model that simulates infection with HIV or Neisseria gonorrhoeae (NG) among MSM. We examined scenarios with increased percentages of MSM getting tested six monthly, among all MSM or only specific subgroups of MSM (defined according to recent gonorrhoea, number of partners and engagement in condomless anal intercourse (CAI)) and scenarios with reduced intervals between HIV/STI tests. RESULTS: The most efficient strategies were those with increased percentage of MSM getting tested every 6 months among MSM with a recent gonorrhoea diagnosis; or among MSM who had CAI and ≥10 partners; or MSM who had ≥10 partners. Over 10 years, these strategies resulted in 387-718 averted HIV infections and required 29-164 additional HIV tests per averted HIV infection or one to seven additional gonorrhoea tests per averted NG infection. The most effective strategy in reducing HIV transmission was the one where the intervals between tests were reduced by half, followed by the strategy with increased percentage of MSM getting tested every 6 months among all MSM. Over 10 years, these strategies resulted in 1362 and 1319 averted HIV infections, but required 663 and 584 additional HIV tests per averted HIV infection, respectively. CONCLUSIONS: Targeting MSM with recent gonorrhoea diagnosis or MSM with many partners is efficient in terms of HIV/STI tests needed to prevent new HIV or NG infections. Major reductions in HIV incidence can be achieved with consistent HIV/STI testing every 6 months among larger groups, including low-risk MSM. To impede HIV transmission, frequent testing should be combined with other prevention measures.

Ethnically diverse urban transmission networks of Neisseria gonorrhoeae without evidence of HIV serosorting.

OBJECTIVE: We aimed to characterise gonorrhoea transmission patterns in a diverse urban population by linking genomic, epidemiological and antimicrobial susceptibility data. METHODS: Neisseria gonorrhoeae isolates from patients attending sexual health clinics at Barts Health NHS Trust, London, UK, during an 11-month period underwent whole-genome sequencing and antimicrobial susceptibility testing. We combined laboratory and patient data to investigate the transmission network structure. RESULTS: One hundred and fifty-eight isolates from 158 patients were available with associated descriptive data. One hundred and twenty-nine (82%) patients identified as male and 25 (16%) as female; four (3%) records lacked gender information. Self-described ethnicities were: 51 (32%) English/Welsh/Scottish; 33 (21%) white, other; 23 (15%) black British/black African/black, other; 12 (8%) Caribbean; 9 (6%) South Asian; 6 (4%) mixed ethnicity; and 10 (6%) other; data were missing for 14 (9%). Self-reported sexual orientations were 82 (52%) men who have sex with men (MSM); 49 (31%) heterosexual; 2 (1%) bisexual; data were missing for 25 individuals. Twenty-two (14%) patients were HIV positive. Whole-genome sequence data were generated for 151 isolates, which linked 75 (50%) patients to at least one other case. Using sequencing data, we found no evidence of transmission networks related to specific ethnic groups (p=0.64) or of HIV serosorting (p=0.35). Of 82 MSM/bisexual patients with sequencing data, 45 (55%) belonged to clusters of ≥2 cases, compared with 16/44 (36%) heterosexuals with sequencing data (p=0.06). CONCLUSION: We demonstrate links between 50% of patients in transmission networks using a relatively small sample in a large cosmopolitan city. We found no evidence of HIV serosorting. Our results do not support assortative selectivity as an explanation for differences in gonorrhoea incidence between ethnic groups.

Call to action for health systems integration of point-of-care testing to mitigate the transmission and burden of sexually transmitted infections.

OBJECTIVES: In 2016, WHO estimated 376 million new cases of the four main curable STIs: gonorrhoea, chlamydia, trichomoniasis and syphilis. Further, an estimated 290 million women are infected with human papillomavirus. STIs may lead to severe reproductive health sequelae. Low-income and middle-income countries carry the highest global burden of STIs. A large proportion of urogenital and the vast majority of extragenital non-viral STI cases are asymptomatic. Screening key populations and early and accurate diagnosis are important to provide correct treatment and to control the spread of STIs. This article paints a picture of the state of technology of STI point-of-care testing (POCT) and its implications for health system integration. METHODS: The material for the STI POCT landscape was gathered from publicly available information, published and unpublished reports and prospectuses, and interviews with developers and manufacturers. RESULTS: The development of STI POCT is moving rapidly, and there are much more tests in the pipeline than in 2014, when the first STI POCT landscape analysis was published on the website of WHO. Several of the available tests need to be evaluated independently both in the laboratory and, of particular importance, in different points of care. CONCLUSION: This article reiterates the importance of accurate, rapid and affordable POCT to reach universal health coverage. While highlighting the rapid technical advances in this area, we argue that insufficient attention is being paid to health systems capacity and conditions to ensure the swift and rapid integration of current and future STI POCT. Unless the complexity of health systems, including context, institutions, adoption systems and problem perception, are recognised and mapped, simplistic approaches to policy design and programme implementation will result in poor realisation of intended outcomes and impact.

The Views of Patients and Partners Toward Patient-Delivered Partner Therapy for Chlamydia: A Systematic Review.

BACKGROUND: The majority of research on patient-delivered partner therapy (PDPT) has focused on its impact on reinfections. This study aimed to systematically review the evidence regarding the acceptability of PDPT by patients and partners for chlamydia infection. METHODS: Three electronic databases were searched in March 2019 using terms related to PDPT. Studies were included if they reported on patient or partner acceptance of PDPT for chlamydia and were conducted in high-income countries. Actual and perceived acceptabilities of PDPT were assessed. RESULTS: Thirty-three studies were included: 24 quantitative, 3 qualitative, and 6 mixed methods. Most were clinic based. Quantitative data showed that participants' perceived willingness to give PDPT to their partner(s) ranged from 44.7% to 96.3% (median, 84%), and 24% to 71% (median, 65%) of people who offered PDPT for their partner(s) accepted it. Partners' perceived willingness to accept ranged from 42.7% to 67% (median, 62%), and actual acceptance ranged from 44.7% to 80% (median, 77%). Those in longer-term relationships were generally more likely to accept PDPT; however, beyond this, we identified few clear trends. Qualitative studies found that convenience of PDPT and assurance of partner treatment were benefits, whereas partners not seeing a health care professional was viewed as a downside. Packaging that appeared legitimate and coaching on delivering PDPT were facilitators. CONCLUSIONS: Because patients bear responsibility for the success of PDPT, this information is crucial in clinical settings. Acceptance, perceived and real, of PDPT was generally high. Patients are best placed to determine whether PDPT is appropriate for them, and it should be offered as an option.

The Potential Population-Level Impact of Different Gonorrhea Screening Strategies in Baltimore and San Francisco: An Exploratory Mathematical Modeling Analysis.

BACKGROUND: Baltimore and San Francisco represent high burden areas for gonorrhea in the United States. We explored different gonorrhea screening strategies and their comparative impact in the 2 cities. METHODS: We used a compartmental transmission model of gonorrhea stratified by sex, sexual orientation, age, and race/ethnicity, calibrated to city-level surveillance data for 2010 to 2017. We analyzed the benefits of 5-year interventions which improved retention in care cascade or increased screening from current levels. We also examined a 1-year outreach screening intervention of high-activity populations. RESULTS: In Baltimore, annual screening of population aged 15 to 24 years was the most efficient of the 5-year interventions with 17.9 additional screening tests (95% credible interval [CrI], 11.8-31.4) needed per infection averted while twice annual screening of the same population averted the most infections (5.4%; 95% CrI, 3.1-8.2%) overall with 25.3 (95% CrI, 19.4-33.4) tests per infection averted. In San Francisco, quarter-annual screening of all men who have sex with men was the most efficient with 16.2 additional (95% CrI, 12.5-44.5) tests needed per infection averted, and it also averted the most infections (10.8%; 95% CrI, 1.2-17.8%). Interventions that reduce loss to follow-up after diagnosis improved outcomes. Depending on the ability of a short-term outreach screening to screen populations at higher acquisition risk, such interventions can offer efficient ways to expand screening coverage. CONCLUSIONS: Data on gonorrhea prevalence distribution and time trends locally would improve the analyses. More focused intervention strategies could increase the impact and efficiency of screening interventions.

A dynamic power-law sexual network model of gonorrhoea outbreaks.

Human networks of sexual contacts are dynamic by nature, with partnerships forming and breaking continuously over time. Sexual behaviours are also highly heterogeneous, so that the number of partners reported by individuals over a given period of time is typically distributed as a power-law. Both the dynamism and heterogeneity of sexual partnerships are likely to have an effect in the patterns of spread of sexually transmitted diseases. To represent these two fundamental properties of sexual networks, we developed a stochastic process of dynamic partnership formation and dissolution, which results in power-law numbers of partners over time. Model parameters can be set to produce realistic conditions in terms of the exponent of the power-law distribution, of the number of individuals without relationships and of the average duration of relationships. Using an outbreak of antibiotic resistant gonorrhoea amongst men have sex with men as a case study, we show that our realistic dynamic network exhibits different properties compared to the frequently used static networks or homogeneous mixing models. We also consider an approximation to our dynamic network model in terms of a much simpler branching process. We estimate the parameters of the generation time distribution and offspring distribution which can be used for example in the context of outbreak reconstruction based on genomic data. Finally, we investigate the impact of a range of interventions against gonorrhoea, including increased condom use, more frequent screening and immunisation, concluding that the latter shows great promise to reduce the burden of gonorrhoea, even if the vaccine was only partially effective or applied to only a random subset of the population.

The Impact of Pre-exposure Prophylaxis for Human Immunodeficiency Virus on Gonorrhea Prevalence.

Pre-exposure prophylaxis (PrEP) has been shown to be highly effective in reducing the risk of HIV infection in gay and bisexual men who have sex with men (GbMSM). However, PrEP does not protect against other sexually transmitted infections (STIs). In some populations, PrEP has also led to riskier behavior such as reduced condom usage, with the result that the prevalence of bacterial STIs like gonorrhea has increased. Here, we develop a compartmental model of the transmission of HIV and gonorrhea and the impacts of PrEP, condom usage, STI testing frequency and potential changes in sexual risk behavior stemming from the introduction of PrEP in a population of GbMSM. We find that introducing PrEP causes an increase in gonorrhea prevalence for a wide range of parameter values, including at the currently recommended frequency of STI testing once every three months for individuals on PrEP. Moreover, the model predicts that a higher STI testing frequency alone is not enough to prevent a rise in gonorrhea prevalence, unless the testing frequency is increased to impractical levels. However, testing every 2 months in combination with a 10-25 % reduction in risky behavior by individuals on PrEP would maintain gonorrhea prevalence at pre-PrEP levels. The results emphasize that programs making PrEP more available should be accompanied by efforts to support condom usage and frequent STI testing, in order to avoid an increase in the prevalence of gonorrhea and other bacterial STIs.

Oropharyngeal Gonorrhea in Absence of Urogenital Gonorrhea in Sexual Network of Male and Female Participants, Australia, 2018.

We describe a sexual network consisting of 1 nonbinary-gendered participant and 2 male and 4 female participants in Australia, 2018. Six of 7 participants had oropharyngeal gonorrhea in the absence of urogenital gonorrhea. This observation supports a new paradigm of gonorrhea transmission in which oropharyngeal gonorrhea can be transmitted through tongue kissing.

Emergence and Spread of Cephalosporin-Resistant Neisseria gonorrhoeae with Mosaic penA Alleles, South Korea, 2012-2017.

In South Korea, surveillance of antimicrobial drug resistance in Neisseria gonorrhoeae is extremely limited. We describe the emergence and subsequent national spread of N. gonorrhoeae strains with mosaic penA alleles associated with decreased susceptibility and resistance to extended-spectrum cephalosporins. From 2012 through 2017, the proportion of mosaic penA alleles in gonococcal-positive nucleic acid amplification test (NAAT) specimens across South Korea increased from 1.1% to 23.9%. Gonococcal strains with mosaic penA alleles emerged in the international hubs of Seoul in Gyeonggi Province and Busan in South Gyeongsang Province and subsequently spread across South Korea. Most common was mosaic penA-10.001 (n = 572 isolates; 94.7%), which is associated with cefixime resistance. We also identified mosaic penA-34.001 and penA-60.001, both of which are associated with multidrug-resistant gonococcal strains and spread of cefixime and ceftriaxone resistance. Implementation of molecular resistance prediction from N. gonorrhoeae-positive nucleic acid amplification test specimens is imperative in South Korea and internationally.

Kissing may be an important and neglected risk factor for oropharyngeal gonorrhoea: a cross-sectional study in men who have sex with men.

OBJECTIVES: A mathematical model suggested that a significant proportion of oropharyngeal gonorrhoea cases are acquired via oropharynx-to-oropharynx transmission (ie, tongue-kissing), but to date, no empirical study has investigated this. This study aimed to examine the association between kissing and oropharyngeal gonorrhoea among gay and bisexual men who have sex with men (MSM). METHODS: MSM attending a public sexual health centre in Melbourne, Australia, between March 2016 and February 2017 were invited to participate in a brief survey that collected data on their number of male partners in the last 3 months, in three distinct categories: kissing-only (ie, no sex including no oral and/or anal sex), sex-only (ie, any sex without kissing), and kissing-with-sex (ie, kissing with any sex). Univariable and multivariable logistic regression analyses were performed to examine associations between oropharyngeal gonorrhoea positivity by nucleic acid amplification tests and the three distinct partner categories. RESULTS: A total of 3677 men completed the survey and were tested for oropharyngeal gonorrhoea. Their median age was 30 (IQR 25-37) and 6.2% (n=229) had oropharyngeal gonorrhoea. Men had a mean number of 4.3 kissing-only, 1.4 sex-only, and 5.0 kissing-with-sex partners in the last 3 months. Kissing-only and kissing-with-sex were associated with oropharyngeal gonorrhoea, but sex-only was not. The adjusted odds for having oropharyngeal gonorrhoea were 1.46-fold (95% CI 1.04 to 2.06) for men with ≥4 kissing-only partners and 1.81-fold (95% CI 1.17 to 2.79) for men with ≥4 kissing-with-sex partners. CONCLUSIONS: These data suggest that kissing may be associated with transmission of oropharyngeal gonorrhoea in MSM, irrespective of whether sex also occurs.

Evidence for a new paradigm of gonorrhoea transmission: cross-sectional analysis of Neisseria gonorrhoeae infections by anatomical site in both partners in 60 male couples.

OBJECTIVE: Gonorrhoea transmission between men is currently thought to occur primarily to and from the urethra. Transmission without urethral involvement, from throat-to-throat and throat-to-anus, is considered to be uncommon. Using gonorrhoea results from male couples, we aimed to investigate the transmission dynamics of gonorrhoea. If current medical consensus is correct, then most throat and anal infections should be explained by the partner's urethral infection. METHODS: This is a cross-sectional analysis of gonorrhoea diagnosed by nucleic acid amplification tests in both partners in male couples who attended Melbourne Sexual Health Centre together between March 2015 and June 2017. Isolates obtained from culture-positive infections underwent whole genome sequencing to assess phylogenetic relatedness between partners. RESULTS: In all 60 couples (120 men) at least one partner had gonorrhoea, and isolates had very high phylogenetic relatedness between partners. After excluding men with urethral gonorrhoea, among 32 men with anal gonorrhoea, 34% (95% CI 19% to 53 %) had a partner with throat gonorrhoea. After excluding couples where either man had urethral gonorrhoea, among 48 couples in which at least one man had throat gonorrhoea, in 23% (95% CI 12% to 37 %) of couples both men had throat gonorrhoea. CONCLUSIONS: The observed gonorrhoea positivity when urethral infection is absent supports a new paradigm of gonorrhoea transmission, where the throat is a major source of gonorrhoea transmission between men, through tongue kissing, oroanal sex and saliva use as anal lubricant. Public health messages may need to address the risk of saliva exposure during sex.

Risk of Gonococcal Infection During Vaginal Exposure is Associated With High Vaginal pH and Active Menstruation.

BACKGROUND: An understanding of the biological reasons why 25% to 35% of women resist infection during vaginal intercourse with a man infected with Neisseria gonorrhoeae could lead to novel control measures. We sought modifiable biological bases for infection resistance by comparing women in the same core-mixing group who did or did not become infected after sexual exposure. METHODS: We enrolled 61 female contacts of index men with gonorrhea seen at Baltimore City Health Department clinics from January 2008 through May 2012. Exposure and sexual practices and histories, co-infections, physical signs on exam, patient symptom report, and menstrual history were collected. RESULTS: Thirty-eight (62.3%) of the exposed women developed cervical infections. Multiple logistic regression found that a vaginal pH of 4.5 or higher at presentation to clinic was significantly associated with gonococcal infection (adjusted odds ratio, 5.5; P = 0.037) in women who presented within one menstrual cycle, 35 days. In this group of women, there was a significant association between acquiring an N. gonorrhoeae cervical infection and sexual exposure during menstruation (adjusted odds ratio 12.5; P = 0.05). CONCLUSIONS: Modification of vaginal pH could be explored as novel strategy for reducing the risk of N. gonorrhoeae infections in women.

Assessing Uncertainty in an Anatomical Site-Specific Gonorrhea Transmission Model of Men Who Have Sex With Men.

BACKGROUND: Increased gonorrhea detection highlights the need for additional prevention efforts. Gonorrhea may only be acquired when there is contact between infected and uninfected anatomical sites. With 3 sites of infection, this leads to 7 plausible routes of men who have sex with men (MSM) transmission: urethra-to-rectum, rectum-to-urethra, urethra-to-oropharynx, rectum-to-oropharynx, oropharynx-to-urethra, oropharynx-to-rectum, and oropharynx-to-oropharynx. We characterize the uncertainty and potential importance of transmission from each anatomical site using a deterministic compartmental mathematical model. METHODS: We developed a model of site-specific gonococcal infection, where individuals are infected at 0, 1, 2, or all 3 sites. Sexual behavior and infection duration parameters were fixed similar to a recent model analysis of Australian MSM. Markov chain Monte Carlo methods were used to sample the posterior distribution of transmission probabilities that were consistent with site-specific prevalence in American MSM populations under specific scenarios. Scenarios were defined by whether transmission routes may or may not transmit by constraining specific transmission probabilities to zero rather than fitting them. RESULTS: Transmission contributions from each site have greater uncertainty when more routes may transmit; in the most extreme case, when all routes may transmit, the oropharynx can contribute 0% to 100% of all transmissions. In contrast, when only anal or oral sex may transmit, transmission from the oropharynx can account for only 0% to 25% of transmission. Intervention effectiveness against transmission from each site also has greater uncertainty when more routes may transmit. CONCLUSIONS: Even under ideal conditions (ie, when site-specific gonococcal prevalence, relative rates of specific sex acts, and duration of infection at each anatomical site are known and do not vary), the relative importance of different anatomical sites for gonococcal infection transmission cannot be inferred with precision. Additional data informing per act transmissibility are needed to understand site-specific gonococcal infection transmission. This understanding is essential for predicting population-specific intervention effectiveness.

Proportion of Incident Human Immunodeficiency Virus Cases Among Men Who Have Sex With Men Attributable to Gonorrhea and Chlamydia: A Modeling Analysis.

BACKGROUND: Sexually transmitted infections (STIs) are associated with an increased risk of human immunodeficiency virus (HIV) acquisition and transmission. We estimated the proportion of HIV incidence among men who have sex with men attributable to infection with the 2 most common bacterial STIs, Neisseria gonorrhoeae (NG) and Chlamydia trachomatis (CT). METHODS: We used a stochastic, agent-based model of a sexual network of MSM with cocirculating HIV, NG, and CT infections. Relative risk (RR) multipliers, specific to anatomic site of infection, modified the risk of HIV transmission and acquisition based on STI status. We estimated the effect of NG and CT on HIV incidence overall and on HIV acquisition and HIV transmission separately. Each scenario was simulated for 10 years. The population attributable fraction (PAF) was determined for each combination of RRs by comparing the incidence in the final year of a scenario to a scenario in which the RRs associated with NG and CT were set to 1.0. RESULTS: Overall, 10.2% (interquartile range [IQR], 7.9-12.4) of HIV infections were attributable to NG/CT infection. Then in sensitivity analyses, the PAF for HIV transmission ranged from 3.1% (IQR, 0.5-5.2) to 20.4% (IQR, 17.8-22.5) and the PAF for HIV acquisition ranged from 2.0% (IQR, -0.7 to 4.3) to 13.8% (IQR, 11.7-16.0). CONCLUSIONS: Despite challenges in estimating the causal impact of NG/CT on HIV risk, modeling is an alternative approach to quantifying plausible ranges of effects given uncertainty in the biological cofactors. Our estimates represent idealized public health interventions in which STI could be maximally prevented, setting targets for real-world STI interventions that seek to reduce HIV incidence.

Associations Between Cannabis Use, Sexual Behavior, and Sexually Transmitted Infections/Human Immunodeficiency Virus in a Cohort of Young Men Who Have Sex With Men.

BACKGROUND: Among men who have sex with men (MSM) the relationship between sexually transmitted infections (STIs) and cannabis use is not well established. We assessed cannabis use, sexual behavior, and STIs including human immunodeficiency virus (HIV) in a diverse cohort of young MSM. METHODS: In Los Angeles, the mSTUDY cohort conducted visits every 6 months with 512 MSM between 2014 and 2017 collecting demographics, sexual behaviors, and reports of frequency of substance use. Each visit conducted testing for gonorrhea, chlamydia, and syphilis via blood, urine, and pharyngeal and rectal swabs by PCR, Human immunodeficiency virus was assessed using rapid tests for HIV-negatives and viral load for HIV-positives. We analyzed the relationship between cannabis use, sexual behaviors and STIs/HIV across 1535 visits. RESULTS: Significantly fewer participants tested positive for STIs at visits when reporting the previous 6 months use of only cannabis (11.7%) compared with no drugs (16.3%) or other drugs (20.0%, P = 0.01). Fewer MSM reporting only cannabis use than no or other drug use had been incarcerated, had incarcerated partners, experienced interpersonal violence, and were HIV-positive. In multivariable analyses visits with positive STIs were associated with other drug use (adjusted odds ratio, 1.69; 95% confidence interval, 1.03-2.78) but not use of cannabis only or no drug use after controlling for age, HIV status, new sex partners, and number of sex partners. CONCLUSIONS: When MSM reported using cannabis exclusively fewer STIs were detected and lower risk sexual engagements reported than when MSM reported no drug or other drug use.