The impact of COVID-19-related restrictions in 2020 on sexual healthcare use, pre-exposure prophylaxis use, and sexually transmitted infection incidence among men who have sex with men in Amsterdam, the Netherlands.

OBJECTIVES: We studied the effects of restrictions related to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2; coronavirus disease 2019 [COVID-19]) pandemic on the use of sexual healthcare and pre-exposure prophylaxis (PrEP) and on the incidence of sexually transmitted infections (STIs) among men who have sex with men (MSM) in a prospective, open-label PrEP demonstration study (AMPrEP) in Amsterdam, the Netherlands. METHODS: We retrieved data from 2019 to 2020 for participants with one or more study visit in 2019 (n = 305) and from two COVID-19 questionnaires (2020: n = 203; 2021: n = 160). Analyses were stratified for three periods of pandemic-related restrictions (first: 15 March 2020-15 June 2020; second: 16 June 2020-15 September 2020; third: 16 September 2020-31 December 2020 or 1 April 2021 for the COVID-19 questionnaire). Endpoints included returning for care during the pandemic, PrEP use (increased/unchanged vs. deceased/stopped, relative to 2019), and any STI/HIV. We modelled determinants of care and PrEP use via multivariable logistic regression and STI incidence using piecewise Poisson regression, comparing the 2020 and 2019 periods. RESULTS: Of the 305 MSM included in the analysis, 72.8% returned for care during the pandemic, and this was significantly more likely among daily (vs. event-driven) PrEP users (p < 0.001). Increased/unchanged PrEP use ranged from 55.2% to 58.1% across the three pandemic periods and was more likely among those reporting chemsex in the first (p = 0.001) and third (p = 0.020) periods and among those reporting an increased/unchanged number of sex partners during the second period (p = 0.010). STI incidence was significantly lower in 2020 than in 2019 during the first period (incidence rate ratio [IRR] 0.43; 95% confidence interval [CI] 0.28-0.68) and not significantly different during the second (IRR 1.38; 95% CI 0.95-2.00) and third (IRR 1.42; 95% CI 0.86-2.33) periods. No HIV was diagnosed. CONCLUSION: COVID-19-related restrictions coincided with reduced care and PrEP use. Changes in STI incidence suggest delayed diagnoses. Ways to ensure continued access to sexual healthcare during restrictions are needed.

Dengue, chikungunya and Zika virus infections among Dutch travellers to Suriname: a prospective study during the introduction of chikungunya and Zika virus, 2014 to 2017.

BackgroundSuriname, a country endemic for dengue virus (DENV), is a popular destination for Dutch travellers visiting friends and relatives and tourist travellers. Chikungunya and Zika virus (CHIKV, ZIKV) were introduced in 2014 and 2015, respectively. Data on infection risks among travellers are limited.AimWe aimed to prospectively study incidence rate (IR) and determinants for DENV, ZIKV and CHIKV infection in adult travellers to Suriname from 2014 through 2017.MethodsParticipants kept a travel diary and were tested for anti-DENV, anti-ZIKV and anti-CHIKV IgG antibodies (Euroimmun). Selected samples were subjected to an in-house DENV and ZIKV PRNT50. The IR (infections/1,000 person-months of travel) and IR ratio and determinants for infection were calculated.ResultsTravel-acquired infections were found in 21 of 481 participants: 18 DENV, four ZIKV and two CHIKV, yielding an IRDENV of 47.0 (95% CI: 29.6-74.6), IRZIKV of 11.6 (95% CI: 4.4-31.0) and IRCHIKV of 5.6 (95% CI: 1.4-22.2)/1,000 person-months. In nine DENV and three ZIKV infected participants, infections were PRNT50-confirmed, yielding a lower IRDENV of 23.3 (95% CI: 12.1-44.8) and an IRZIKV of 8.4 (95% CI: 2.7-26.1) per 1,000 person-months. Tourist travel was associated with DENV infection. ZIKV and CHIKV infections occurred soon after their reported introductions.ConclusionsDespite an overestimation of serologically confirmed infections, Dutch travellers to Suriname, especially tourists, are at substantial risk of DENV infection. As expected, the risk of contracting ZIKV and CHIKV was highest during outbreaks. Cross-reaction and potential cross-protection of anti-DENV and -ZIKV antibodies should be further explored.

Evolution of Coronavirus Disease 2019 (COVID-19) Symptoms During the First 12 Months After Illness Onset.

BACKGROUND: Few robust longitudinal data on long-term coronavirus disease 2019 (COVID-19) symptoms are available. We evaluated symptom onset, severity and recovery across the full spectrum of disease severity, up to one year after illness onset. METHODS: The RECoVERED Study is a prospective cohort study based in Amsterdam, the Netherlands. Participants aged ≥18 years were enrolled following severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) diagnosis via the local public health service and from hospitals. Standardized symptom questionnaires were completed at enrollment, 1 week and month later, and monthly thereafter. Clinical severity was defined according to World Health Organization (WHO) criteria. Kaplan-Meier methods were used to compare time from illness onset to symptom recovery, by clinical severity. We examined determinants of time to recovery using multivariable Cox proportional hazards models. RESULTS: Between 11 May 2020 and 1 May 2021, 342 COVID-19 patients (192 [56%] male) were enrolled, of whom 99/342 (29%) had mild, 145/342 (42%) moderate, 56/342 (16%) severe, and 42/342 (12%) critical disease. The proportion of participants who reported at least 1 persistent symptom at 12 weeks after illness onset was greater in those with severe/critical disease (86.7% [95% confidence interval {CI} = 76.5-92.7%]) compared to those with mild or moderate disease (30.7% [95% CI = 21.1-40.9%] and 63.8% [95% CI = 54.8-71.5%], respectively). At 12 months after illness onset, two-fifths of participants (40.7% [95% CI = 34.2-7.1]) continued to report ≥1 symptom. Recovery was slower in female compared to male participants (adjusted hazard ratio [aHR] 0.65 [95% CI = .47-.92]) and those with a body mass index [BMI]  ≥30kg/m2 compared to BMI <25kg/m2 (hazard ratio [HR] 0.62 [95% CI = .39-.97]). CONCLUSIONS: COVID-19 symptoms persisted for one year after illness onset, even in some individuals with mild disease. Female sex and obesity were the most important determinants of speed of recovery from symptoms.

Quantifying heterogeneity in sexual behaviour and distribution of STIs before and after pre-exposure prophylaxis among men who have sex with men.

Objectives: Pre-exposure prophylaxis (PrEP) use may influence sexual behaviour and transmission of STIs among men who have sex with men (MSM). We aimed to quantify the distribution of STI diagnoses among MSM in the Netherlands based on their sexual behaviour before and after the introduction of PrEP. Methods: HIV-negative MSM participating in a prospective cohort study (Amsterdam Cohort Studies) completed questionnaires about sexual behaviour and were tested for STI/HIV during biannual visits (2009-2019). We developed a sexual behaviour risk score predictive of STI diagnosis and used it to calculate Gini coefficients for gonorrhoea, chlamydia and syphilis diagnoses in the period before (2009 to mid-2015) and after PrEP (mid-2015 to 2019). Gini coefficients close to zero indicate that STI diagnoses are homogeneously distributed over the population, and close to one indicate that STI diagnoses are concentrated in individuals with a higher risk score. Results: The sexual behaviour risk score (n=630, n visits=10 677) ranged between 0.00 (low risk) and 3.61 (high risk), and the mean risk score increased from 0.70 (SD=0.66) before to 0.93 (SD=0.80) after PrEP. Positivity rates for chlamydia (4%) and syphilis (1%) remained relatively stable, but the positivity rate for gonorrhoea increased from 4% before to 6% after PrEP. Gini coefficients increased from 0.37 (95% CI 0.30 to 0.43) to 0.43 (95% CI 0.36 to 0.49) for chlamydia, and from 0.37 (95% CI 0.19 to 0.52) to 0.50 (95% CI 0.32 to 0.66) for syphilis comparing before to after PrEP. The Gini coefficient for gonorrhoea remained stable at 0.46 (95% CI 0.40 to 0.52) before and after PrEP. Conclusions: MSM engaged in more high-risk sexual behaviour and gonorrhoea diagnoses increased after PrEP was introduced. Chlamydia and syphilis diagnoses have become more concentrated in a high-risk subgroup. Monitoring the impact of increasing PrEP coverage on sexual behaviour and STI incidence is important. Improved STI prevention is needed, especially for high-risk MSM.

How the Disruption in Sexually Transmitted Infection Care Due to the COVID-19 Pandemic Could Lead to Increased Sexually Transmitted Infection Transmission Among Men Who Have Sex With Men in The Netherlands: A Mathematical Modeling Study.

BACKGROUND: During the COVID-19 pandemic, the disruption in care for sexually transmitted infections (STIs) and the social distancing measures have led to reductions in STI testing and sexual behavior. We assessed the impact of these COVID-19-related changes on transmission of Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) among men who have sex with men (MSM) in The Netherlands. METHODS: We developed a mathematical model for CT and NG transmission among MSM, accounting for COVID-19-related changes in sexual behavior and testing in 2020 to 2021. Changes in 2020 were estimated from data from the Dutch COVID-19, Sex, and Intimacy Survey among MSM and the National Database of STI Clinics. Because of the lack of data for 2021, we examined several scenarios covering a range of changes. RESULTS: A reduction of 10% and 40% in STI testing of symptomatic and asymptomatic, respectively, individuals with a 10% to 20% reduction in numbers of casual partners (according to partner status and activity level) during the second lockdown, resulted in a 2.4% increase in CT prevalence, but a 2.8% decline in NG prevalence in 2021. A 5% and 30% reduction in STI testing of symptomatic and asymptomatic, respectively, individuals with the same reduction in casual partners resulted in a 0.6% increase in CT prevalence and a 4.9% decrease in NG prevalence in 2021. CONCLUSIONS: The disruption in STI care due to COVID-19 might have resulted in a small increase in CT prevalence, but a decrease in NG prevalence. Scaling up STI care is imperative to prevent increases in STI transmission.

Factors Associated With the Intention to Use HIV Preexposure Prophylaxis for Young and Older Men Who Have Sex With Men.

BACKGROUND: The uptake of preexposure prophylaxis (PrEP) against HIV is low among young men who have sex with men (MSM) in the Netherlands. Studying the intention to use PrEP among non-PrEP using young and older MSM can guide health authorities in developing new prevention campaigns to optimize PrEP uptake. METHODS: We investigated the sociodemographic, behavioral, and psychosocial factors associated with a high PrEP use intention in the coming 6 months among 93 young MSM (aged ≤25 years), participating in an online survey, and 290 older MSM (aged ≥26 years), participating in an open, prospective cohort in 2019 to 2020. RESULTS: Perceiving PrEP as an important prevention tool was associated with a high PrEP use intention among young and older MSM. Among young MSM, a high level of PrEP knowledge and believing that PrEP users take good care of themselves and others were associated with a high PrEP use intention. Among older MSM, 2 or more anal sex partners, chemsex, high HIV risk perception, and believing PrEP increases sexual pleasure were associated with a high PrEP use intention. Believing PrEP leads to adverse effects was associated with a low intention to use PrEP among older MSM. CONCLUSIONS: To conclude, we showed that both behavioral and psychosocial factors were associated with a high PrEP use intention among young and older MSM. In addition to focusing on sexual behavior and HIV risk, future prevention campaigns and counseling on PrEP could incorporate education, endorsing positive beliefs, and disarming negative beliefs to improve the uptake of PrEP in young and older MSM.

Eligibility criteria vs. need for pre-exposure prophylaxis: a reappraisal among men who have sex with men in Amsterdam, the Netherlands.

To reappraise pre-exposure prophylaxis (PrEP) eligibility criteria towards the men who have sex with men (MSM) with highest HIV-risk, we assessed PrEP need (i.e. HIV-risk) using Amsterdam Cohort Studies data from 2011-2017 for all non-PrEP using MSM. Outcomes were incident HIV-infection and newly-diagnosed anal STI. Determinants were current PrEP eligibility criteria (anal STI and condomless sex (CAS)) and additional determinants (age, education, group sex, alcohol use during sex and chemsex). We used targeted maximum likelihood estimation (TMLE) to estimate the relative risk (RR) and 95% confidence intervals (CI) of determinants on outcomes, and calculated population attributable fractions (PAFs) with 95% CI using RRs from TMLE. Among 810 included MSM, 22 HIV-infections and 436 anal STIs (n = 229) were diagnosed during follow-up. Chemsex (RR = 5.8 (95% CI 2.0-17.0); PAF = 55.3% (95% CI 43.3-83.4)), CAS with a casual partner (RR = 3.3 (95% CI 1.3-8.7); PAF = 38.0% (95% CI 18.3-93.6)) and anal STI (RR = 5.3 (95% CI 1.7-16.7); PAF = 22.0 (95% CI -16.8 to 100.0)) were significantly (P < 0.05) associated with and had highest attributable risk fractions for HIV. Chemsex (RR = 2.0 (95% CI 1.6-2.4); PAF = 19.5 (95% CI 10.6-30.6)) and CAS with a casual partner (RR = 2.5 (95% CI 2.0-3.0); PAF = 28.0 (95% CI 21.0-36.4)) were also significantly associated with anal STI, as was younger age (16-34/≥35; RR = 1.7 (95% CI 1.4-2.1); PAF = 15.5 (95% CI 6.4-27.6)) and group sex (RR = 1.3 (95% CI 1.1-1.6); PAF = 9.0 (95% CI -2.3 to 23.7)). Chemsex should be an additional PrEP eligibility criterion.

Incidence of HCV Reinfection Among HIV-Positive MSM and Its Association With Sexual Risk Behavior: A Longitudinal Analysis.

BACKGROUND: Human immunodeficiency virus (HIV)-positive men who have sex with men (MSM) are at high risk of hepatitis C virus (HCV) reinfection following clearance of HCV, but risk factors specifically for reinfection have never been comprehensively assessed. METHODS: Using data from a prospective observational cohort study among HIV-positive MSM with an acute HCV infection (MOSAIC), the incidence of HCV reinfection following spontaneous clearance or successful treatment was assessed. A univariable Bayesian exponential survival model was used to identify risk factors associated with HCV reinfection. RESULTS: In total, 122 HIV-positive MSM who had a spontaneously cleared or successfully treated HCV infection between 2003 and 2017 were included. During a median follow-up of 1.4 years (interquartile range [IQR] 0.5-3.8), 34 HCV reinfections were observed in 28 patients. The incidence of HCV reinfection was 11.5/100 person-years and among those with reinfection, median time to reinfection was 1.3 years (IQR 0.6-2.7). HCV reinfection was associated with receptive condomless anal intercourse, sharing of sex toys, group sex, anal rinsing before sex, ≥10 casual sex partners in the last 6 months, nadir CD4 cell count <200 cells/mm3, and recent CD4 cell count <500 cells/mm3. CONCLUSIONS: Incidence of HCV reinfection was high and strongly associated with sexual risk behavior, highlighting the need for interventions to reduce risk behavior and prevent HCV reinfections among HIV-positive MSM.

Eligibility for HIV Preexposure Prophylaxis, Intention to Use Preexposure Prophylaxis, and Informal Use of Preexposure Prophylaxis Among Men Who Have Sex With Men in Amsterdam, the Netherlands.

BACKGROUND: Before 2019, availability of affordable HIV preexposure prophylaxis (PrEP) was limited in the Netherlands. Consequently, some men who have sex with men and transgender persons obtained PrEP informally, that is, without a prescription. METHODS: Between September 2017 and August 2018, we enrolled informal PrEP users in a cohort study (Informal PrEP [InPrEP]) at the Amsterdam Sexually Transmitted Infections (STI) Clinic. We compared PrEP use, PrEP eligibility and intention, chemsex, and STI positivity between 3 groups: (1) informal PrEP users enrolled in InPrEP, (2) nonenrolled informal PrEP users, and (3) non-PrEP users. Also, we assessed intention and associated characteristics among non-PrEP users who were eligible for PrEP. RESULTS: During the study period, we enrolled 118 informal PrEP users in InPrEP who were compared with 224 nonenrolled informal PrEP users and 4975 non-PrEP users. Preexposure prophylaxis eligibility rates were 83.1%, 93.4%, and 63.0%; chemsex were reported by 39.1%, 48.1%, and 11.7%; and STI positivity was reported by 28.0%, 42.5%, and 20.3%, respectively. Among PrEP-eligible non-PrEP users, PrEP intention was 16.6% and associated with increasing age, non-Dutch origin, higher educational level, receptive condomless anal sex, increasing number of sex partners, chemsex, and sex with men only. CONCLUSIONS: Most informal PrEP users are eligible to use PrEP and have a clear sexual health care need. Especially in settings with limited PrEP access, providing the necessary care for informal PrEP users is important. The intention to use PrEP is low among PrEP-eligible STI clinic visitors. Further research should investigate modes to increase PrEP intention among PrEP-eligible persons.

The Burden of Living With HIV is Mostly Overestimated by HIV-Negative and Never-Tested Men Who Have Sex With Men.

To assess whether HIV-negative men who have sex with men (MSM) have realistic views of the current implications of living with HIV, we compared data of 950 tested HIV-negative and 122 never-tested MSM on anticipated consequences of an HIV-infection to the actual experiences of 438 MSM living with HIV. Data were collected with a self-reported, web-based survey conducted between May-June 2019 in the Netherlands. Results indicated that, compared to HIV-positive MSM, HIV-negative MSM significantly overestimated 95% (37/39) of items assessing HIV-related burden. Never-tested participants overestimated 85% (33/39) of items. Overestimation in never-tested MSM was modified with increasing age and having HIV-positive friends/relatives. The high level of overestimation suggests the ongoing need to correct for misperceptions, as this could help reduce stigma towards those living with HIV and diminish fear of an HIV-diagnosis. The latter might be important to improve testing uptake in older never-tested MSM with outdated views on HIV.

The Rhythm of Risk: Sexual Behaviour, PrEP Use and HIV Risk Perception Between 1999 and 2018 Among Men Who Have Sex with Men in Amsterdam, The Netherlands.

HIV risk perception plays a crucial role in the uptake of preventive strategies. We investigated how risk perception and its determinants changed between 1999 and 2018 in an open, prospective cohort of 1323 HIV-negative men who have sex with men (MSM). Risk perception, defined as the perceived likelihood of acquiring HIV in the past 6 months, changed over time: being relatively lower in 2008-2011, higher in 2012-2016, and again lower in 2017-2018. Irrespective of calendar year, condomless anal intercourse (AI) with casual partners and high numbers of partners were associated with higher risk perception. In 2017-2018, condomless receptive AI with a partner living with HIV was no longer associated with risk perception, while PrEP use and condomless AI with a steady partner were associated with lower risk perception. We showed that risk perception has fluctuated among MSM in the past 20 years. The Undetectable equals Untransmittable statement and PrEP coincided with lower perceived risk.

Types of Group Sex and Their Association with Different Sexual Risk Behaviors Among HIV-Negative Men Who Have Sex with Men.

The current study sought to identify types of group sex acts among HIV-negative men who have sex with men (MSM) and assess their association with different sexual risk behaviors using cross-sectional data of group sex acts reported during 6 waves (2015-2018) of the Amsterdam MSM Cohort Study. Latent class analysis was performed to identify group sex types based on size, familiarity with partners, location, planning, and drug use. Associations between group sex types and sexual behaviors were evaluated using logistic regression with generalized estimating equations, employing the sample mean as a reference. Data at the level of group sex acts were analyzed, while correcting variance estimations for repeated measurements within MSM. A total of 392 MSM engaged in group sex ≥ 1 times, totaling 1033 group sex acts. Four types of group sex emerged: familiar (29%), intimate (27%), impromptu (36%), and party (8%). Familiar group sex (characterized by high proportions of mostly known partners, occurring in private places and involving drug use) had an increased adjusted odds of risky fingering (aOR 1.6, 95%CI 1.3-2.0) and of risky fisting and/or use of sex toys (aOR 2.3, 95%CI 1.6-3.1). Intimate group sex (characterized by high proportions of threesomes, occurring in private places, and not involving drug use) had a decreased adjusted odds of risky fisting and/or use of sex toys (aOR 0.6, 95%CI 0.4-0.9). Impromptu group sex (characterized by high proportions of spontaneity, mostly unknown partners, and taking place in public places) had a decreased adjusted odds of risky fisting and/or use of sex toys (aOR 0.5, 95%CI 0.3-0.7) and of condomless anal intercourse (CAI) (OR 0.6, 95%CI 0.5-0.8). Party group sex (characterized by high proportions of larger groups, mostly unknown partners, and being planned) had an increased adjusted odds of risky fisting and/or use of sex toys (aOR 1.6, 95%CI 1.0-2.7) and of CAI (aOR 1.5, 95%CI 1.1-2.1). The identified types of group sex reflect different dynamics and characteristics, with some types riskier for STIs and others riskier for HIV. HIV and STI prevention efforts could be tailored accordingly. For example, in certain type of public sex environments (e.g., cruising parks), traditional HIV and STI prevention efforts, such as promoting of condom use and PrEP, might be sufficient. However, in other settings (e.g., private parties), where group sex is more likely to be planned and where behaviors such as fisting, sharing of sex toys, and CAI are more likely to take place, which carry different levels of risk for HIV and STI transmission, including that of Hepatitis C, different approaches might be needed, such as broader HIV and STI prevention education efforts or targeting the organizers of group sex events.

Infection Pressure in Men Who Have Sex With Men and Their Suitability to Donate Blood.

BACKGROUND: Deferral of men who have sex with men (MSM) from blood donation is highly debated. We therefore investigated their suitability to donate blood. METHODS: We compared the antibody prevalence of 10 sexually and transfusion-transmissible infections (TTIs) among 583 MSM and 583 age-matched repeat male blood donors. MSM were classified as low risk (lr) or medium-to-high risk (hr) based on self-reported sexual behavior and as qualified or unqualified using Dutch donor deferral criteria. Infection pressure (IP) was defined as the number of antibody-reactive infections, with class A infections (human immunodeficiency virus-1/2, hepatitis B virus, hepatitis C virus, human T-cell lymphotropic virus-1/2, syphilis) given double weight compared to class B infections (cytomegalovirus, herpes simplex virus-1/2, human herpesvirus 8, hepatitis E virus, parvovirus B19). RESULTS: Donors had a lower median IP than qualified lr-MSM and qualified hr-MSM (2 [interquartile range {IQR}, 1-2] vs 3 [IQR, 2-4]; P < .001). Low IP was found in 76% of donors, 39% of qualified lr-MSM, and 27% of qualified hr-MSM. The prevalence of class A infections did not differ between donors and qualified lr-MSM but was significantly higher in qualified hr-MSM and unqualified MSM. Recently acquired class A infections were detected in hr-MSM only. Compared to blood donors, human herpesviruses were more prevalent in all MSM groups (P < .001). CONCLUSIONS: IP correlates with self-reported risk behavior among MSM. Although lr-MSM might form a low threat for blood safety with regard to class A infections, the high seroprevalence of human herpesviruses in lr-MSM warrants further investigation.

The effects of free condom distribution on HIV and other sexually transmitted infections in men who have sex with men.

BACKGROUND: HIV and other sexually transmitted infections remain a burden on men who have sex with men in the era of effective combination antiretroviral therapy. New prevention efforts are therefore needed. One of these approaches is the current country-wide free condom distribution at gay bars with darkrooms and gay saunas in the Netherlands. This study assessed the effects of free condom distribution on incidence and burden of disease of HIV and other sexually transmitted infections. METHODS: A static model was constructed to calculate the impact of free condom distribution on HIV, hepatitis C, chlamydia, gonorrhoea, and syphilis among men who have sex with men visiting these venues. Outcomes included new infections averted and disability-adjusted life years averted. Scenario studies were performed to predict the effects of a further increase of condom use, condom effectiveness and coverage. Lastly, cost-effectiveness and sensitivity analyses were performed. RESULTS: Our model showed that condom use at public sex venues increased after the intervention. Annual incidence risk decreased, ranging from 5.73% for gonorrhoea to 7.62% for HIV. The annual number of new infections averted was largest for chlamydia and gonorrhoea (261 and 394 infections, respectively), but 42 new HIV infections were averted as well. In scenarios where condom use and condom effectiveness were further increased, the number of infections reduced more extensively. Over 99% of the decrease in burden of disease was due to HIV. The intervention was cost-effective and cost-saving (for every €1 spent on condom distribution, €5.51 was saved) and remained this in all sensitivity analyses. CONCLUSIONS: Free condoms at public sex venues could reduce the transmission of HIV and other sexually transmitted infections. Condom distribution is an affordable and easily implemented intervention that could reduce the burden of disease in men who have sex with men substantially.

Model projections on the impact of HCV treatment in the prevention of HCV transmission among people who inject drugs in Europe.

BACKGROUND & AIMS: Prevention of hepatitis C virus (HCV) transmission among people who inject drugs (PWID) is critical for eliminating HCV in Europe. We estimated the impact of current and scaled-up HCV treatment with and without scaling up opioid substitution therapy (OST) and needle and syringe programmes (NSPs) across Europe over the next 10 years. METHODS: We collected data on PWID HCV treatment rates, PWID prevalence, HCV prevalence, OST, and NSP coverage from 11 European settings. We parameterised an HCV transmission model to setting-specific data that project chronic HCV prevalence and incidence among PWID. RESULTS: At baseline, chronic HCV prevalence varied from <25% (Slovenia/Czech Republic) to >55% (Finland/Sweden), and <2% (Amsterdam/Hamburg/Norway/Denmark/Sweden) to 5% (Slovenia/Czech Republic) of chronically infected PWID were treated annually. The current treatment rates using new direct-acting antivirals (DAAs) may achieve observable reductions in chronic prevalence (38-63%) in 10 years in Czech Republic, Slovenia, and Amsterdam. Doubling the HCV treatment rates will reduce prevalence in other sites (12-24%; Belgium/Denmark/Hamburg/Norway/Scotland), but is unlikely to reduce prevalence in Sweden and Finland. Scaling-up OST and NSP to 80% coverage with current treatment rates using DAAs could achieve observable reductions in HCV prevalence (18-79%) in all sites. Using DAAs, Slovenia and Amsterdam are projected to reduce incidence to 2 per 100 person years or less in 10 years. Moderate to substantial increases in the current treatment rates are required to achieve the same impact elsewhere, from 1.4 to 3 times (Czech Republic and France), 5-17 times (France, Scotland, Hamburg, Norway, Denmark, Belgium, and Sweden), to 200 times (Finland). Scaling-up OST and NSP coverage to 80% in all sites reduces treatment scale-up needed by 20-80%. CONCLUSIONS: The scale-up of HCV treatment and other interventions is needed in most settings to minimise HCV transmission among PWID in Europe. LAY SUMMARY: Measuring the amount of HCV in the population of PWID is uncertain. To reduce HCV infection to minimal levels in Europe will require scale-up of both HCV treatment and other interventions that reduce injecting risk (especially OST and provision of sterile injecting equipment).

Determining the Most Likely Source of Infection: An Application to Neisseria Gonorrhoeae Among Men Who Have Sex with Men.

BACKGROUND: The source of an infection is often unknown. To inform directed prevention measures, it is useful to know the location and partner type with the highest transmission risk. We developed a method to estimate infection risk of Neisseria gonorrhoeae per meeting location among men who have sex with men (MSM). METHODS: In 2008-2009, we collected information from 2,438 MSM attending the sexually transmitted infections clinic of Amsterdam. For up to four partners per participant (8,028 in total), we asked for details on meeting location, partner, and partnership characteristics. We used logistic regression to relate these to the participant's infection risk, accounting for unobserved transmission information in the likelihood. Based on the model estimates, we predicted the probability of a partner having N. gonorrhoeae. The probability that a partner was the source was proportional to his predicted infection risk. Each source was linked to the meeting location. We used a Bayesian method. RESULTS: Rectal N. gonorrhoeae was diagnosed in 157 MSM who reported data on 422 possible source partners, urethral N. gonorrhoeae in 126 reporting 285 possible sources, and pharyngeal N. gonorrhoeae in 162 reporting 451 possible sources. We estimated that most infections were acquired from long-lasting steady partners (21%; 95% CI = 17, 24). Partners met in an Amsterdam street with gay venues posed the highest transmission risk (13%; 95% CI = 7.9, 18). CONCLUSIONS: The presented method estimates the source of infection when there are multiple possible sources and enables the summation over various kinds of epidemiologic characteristics (here, meeting locations) that are relevant for prevention.

Stable Low Hepatitis C Virus Antibody Prevalence Among HIV-Negative Men Who Have Sex With Men Attending the Sexually Transmitted Infection Outpatient Clinic in Amsterdam, 2007 to 2017.

BACKGROUND: In response to the increased hepatitis C virus (HCV) prevalence recently found among participants of the Amsterdam preexposure prophylaxis demonstration project, we evaluated HCV prevalence over time and the performance of the HCV-MOSAIC risk score for detection of HCV infection in HIV-negative men who have sex with men (MSM) attending the Amsterdam sexually transmitted infection (STI) clinic. METHODS: In October 2016, HIV-negative MSM were tested for anti-HCV and HCV RNA and completed the HCV-MOSAIC risk score. Anti-HCV prevalence was compared with that found in cross-sectional studies at the Amsterdam STI clinic (2007-2017). The time trend in HCV prevalence was modeled via logistic regression. The performance of the HCV-MOSAIC risk score, adjusted to identify prevalent HCV infection, was evaluated by calculating sensitivity and specificity. RESULTS: Of 504 HIV-negative MSM tested in October 2016, 5 were anti-HCV positive (1.0%, 95% confidence interval [CI], 0.4%-2.3%) and all were HCV RNA negative. Sensitivity and specificity of the adjusted HCV-MOSAIC risk score for prevalent infection were 80.0% (95% CI, 37.6%-96.4%) and 56.1% (95% CI, 51.7%-60.4%), respectively. The overall anti-HCV prevalence among 3264 HIV-negative MSM participating in cross-sectional studies at the Amsterdam STI clinic (2007-2017) was 0.8% (95% CI, 0.5%-1.2%) and did not change over time (P = 0.55). CONCLUSIONS: Anti-HCV prevalence among HIV-negative MSM attending the Amsterdam STI clinic in October 2016 was 1.0% and remained stable over time. We would therefore not recommend routine HCV screening of HIV-negative MSM at the STI clinic. However, given the increased prevalence among MSM using preexposure prophylaxis, periodic monitoring of HCV prevalence remains important.

Differences in Chlamydia trachomatis seroprevalence between ethnic groups cannot be fully explained by socioeconomic status, sexual healthcare seeking behavior or sexual risk behavior: a cross-sectional analysis in the HEalthy LIfe in an Urban Setting (HELIUS) study.

BACKGROUND: In the Netherlands, there are strong disparities in Chlamydia trachomatis (CT) prevalence between ethnic groups. The current study aims to identify whether socioeconomic status, sexual risk behavior and sexual healthcare seeking behavior may explain differences in CT seroprevalence between ethnic groups. METHODS: We used 2011-2014 baseline data of the HELIUS (HEalthy LIfe in an Urban Setting) study, a multi-ethnic population-based cohort study in Amsterdam, the Netherlands, including participants from Dutch, African Surinamese, South-Asian Surinamese, Ghanaian, Moroccan and Turkish origin. For this analysis, we selected sexually active, heterosexual participants aged 18-34 years old. CT seroprevalence was determined using a multiplex serology assay. The CT seroprevalence ratios between different ethnicities are calculated and adjusted for potential indicators of socioeconomic status, sexual risk behavior and sexual healthcare seeking behavior. RESULTS: The study population consisted of 2001 individuals (52.8% female) with a median age of 28 years (IQR 24-31). CT seropositivity differed by ethnicities and ranged from 71.6% (African Surinamese), and 67.9% (Ghanaian) to 31.1% (Turkish). The CT seroprevalence ratio of African Surinamese was 1.72 (95% CI 1.43-2.06) and 1.52 (95% CI 1.16-1.99) of Ghanaian as compared to the Dutch reference group, after adjustment for socioeconomic status, sexual risk behavior and sexual healthcare seeking behavior. CONCLUSIONS: Indicators of socioeconomic status, sexual risk behavior, and sexual health seeking behavior could not explain the higher CT seroprevalence among African Surinamese and Ghanaian residents of Amsterdam.

Does online dating lead to higher sexual risk behaviour? A cross-sectional study among MSM in Amsterdam, the Netherlands.

BACKGROUND: Men having sex with men (MSM) frequently use the Internet to find sex partners. We examined the association between unprotected anal intercourse (UAI) with partners dated online and with partners dated offline (met elsewhere), and examined whether differences can be explained by self-perceived HIV status of the index and knowledge of partnership characteristics. METHODS: MSM were recruited at the Sexually Transmitted Infections Clinic in Amsterdam, in 2008-2009. Participants completed a questionnaire concerning sexual behaviour. Only men reporting both online and offline casual sex partners were included. We assessed the association between online/offline partner dating and UAI, using random-effects logistic regression analysis. RESULTS: Five hundred seventy-seven men (351 HIV-negative, 153 HIV-positive, and 73 HIV-unaware) reported UAI in 26 % of 878 online, and 23 % of 903 offline casual partnerships. The crude OR of online dating for UAI was 1.36 (95 % CI 1.03-1.81). HIV-positive men were more likely to report UAI than HIV-negative men (49 % vs. 28 % of partnerships). Adjusted for demographic characteristics, online dating had no significant effect on UAI among HIV-negative and HIV status-unaware men, but HIV-positive men were more likely to have UAI with online partners (aOR = 1.65 [95 % CI 1.05-2.57]). After correction for partner and partnership characteristics the effect of online/offline dating on UAI among HIV-positive MSM was reduced and no longer significant. CONCLUSIONS: Online dating was not significantly associated with UAI among HIV-negative MSM. HIV-positive MSM were more likely to practise UAI with partners dated online; however, after correction for partner and partnership characteristics, online partnership acquisition was not associated with a significantly increased risk of UAI.

The importance of partnership factors and individual factors associated with absent or inconsistent condom use in heterosexuals: a cross-sectional study.

OBJECTIVES: Decisions to use condoms are made within partnerships. We examined the associations between inconsistent or no condom use and individual and partnership characteristics. We also examined the relative importance of individual versus partnership factors. METHODS: Cross-sectional study of heterosexual individuals enrolled from the sexually transmitted infections (STI) outpatient clinic in Amsterdam, the Netherlands, from May to August 2010. Participants completed a questionnaire about sexual behaviour with the last four partners in the preceding year. Participant and partnership factors associated with inconsistent or no condom use in steady and casual partnerships were identified. RESULTS: 2144 individuals were included, reporting 6401 partnerships; 54.7% were female, the median age was 25 (IQR 22-30) years and 79.9% were Dutch. Inconsistent or no condom use occurred in 86.1% of 2387 steady partnerships and in 66.5% of 4014 casual partnerships. There was statistical evidence of associations between inconsistent condom use in steady partnerships and ethnic concordance, longer duration, higher number of sex acts, practising anal sex, and sex-related drug use. In casual partnerships, associations were found with having an older partner, ethnic concordance, longer duration, higher number of sex acts, anal sex, sex-related drug use, ongoing partnerships and concurrency. In multivariable models, partnership factors explained 50.9% of the variance in steady partnerships and 70.1% in casual partnerships compared with 10.5% and 15.4% respectively for individual factors. CONCLUSIONS: Among heterosexual STI clinic attendees in Amsterdam, partnership factors are more important factors related with inconsistent condom use than characteristics of the individual.