Determinants of HIV Testing Among Migrant Men Who Have Sex With Men from Sub-Saharan Africa and Other Regions Residing in 10 European Countries.

Migrant men who have sex with men (mMSM) from sub-Saharan Africa (SSA) and other regions outside Europe are highly vulnerable to HIV. However, research on the determinants of HIV testing among mMSM from SSA, and how these differ across the categories of mMSM living in Europe, is limited. Using data from the European MSM Internet Survey (EMIS-2017), we assessed HIV testing prevalence and recency in mMSM from SSA and other mMSM residing in ten European countries, as well as the determinants of HIV testing across different mMSM categories with logistic regression analyses. Ever-testing for HIV was slightly higher in mMSM from SSA (83%) compared to other mMSM categories (75-80%), except for mMSM from Latin America and Caribbean region (84%). Overall, 20% of mMSM had never tested. In multivariable analysis, higher age (adjusted odds ratio [AOR] 1.05, 95% confidence interval [CI] 1.01-1.10), higher HIV knowledge (AOR 1.45, 95%-CI 1.11-1.90), and residence in smaller settlements (AOR 0.45, 95%-CI 0.21-0.96) were significantly associated with ever testing for HIV in mMSM from SSA. Comparing mMSM from SSA to mMSM from other regions, we found varying significant similarities (higher age, residence in smaller settlements and HIV knowledge) and differences (lower educational attainment, not identifying as gay, being a student, and limited disclosure of homosexual attraction) in the determinants of ever-testing for HIV. Community-specific interventions addressing identified sociodemographic and behavioral determinants to increase HIV testing uptake in the different mMSM categories and better data for further research are warranted.

Exploring group differences in the response to a sexual risk reduction intervention to prevent hepatitis C virus reinfection in HIV-infected MSM: a mixed-methods study.

To prevent hepatitis C virus (HCV) reinfection, within the Swiss HCVree Trial, a preventive risk reduction intervention was implemented alongside curative treatment. Formative qualitative research identified three response patterns to the intervention. This mixed-methods study's aim was to cross-validate group differences in (a) the content of sexual risk reduction goals set during intervention and (b) the extent of their behavioural change in condomless anal intercourse with non-steady partners (nsCAI), sexualised and intravenous drug use at start and six-month post-intervention. Qualitative thematic analysis was used to summarise goal setting domains. Quantitative descriptive analysis was used to evaluate group differences based on assumptions of the group descriptions. Results largely confirmed assumptions on inter-group response differences in goal setting and behaviour: as expected group 1 Avoid risks showed the lowest HCV risk profile with changes in nsCAI. Group 2 Minimize-risks and Group 3 Accept-risks showed unchanged nsCAI. Group 3 had the highest HCV risk profile. Differences in their goal preferences (1: condom use; 2 reduction blood exposure; 3 safer dating) highlight diversity in attitudes to behavioural change. Our results improve understanding of variability in intervention responses such as changes in attitudes and behaviour. This provides evidence for intervention tailoring and outcome measurement.

Incidence of sexually transmitted infections and association with behavioural factors: Time-to-event analysis of a large pre-exposure prophylaxis (PrEP) cohort.

OBJECTIVES: Our objective was to obtain long-term data on the incidence of sexually transmitted infections (STIs) and their association with behavioural factors after widespread pre-exposure prophylaxis (PrEP) implementation. METHODS: This was a time-to-event analysis of a national PrEP cohort in Switzerland (SwissPrEPared study). Participants were people without HIV interested in taking PrEP with at least two STI screening visits. Primary outcomes were incidence rate of gonorrhoea, chlamydia, and syphilis. The association between behavioural factors and STI diagnosis was expressed using hazard ratios. We adjusted for testing frequency and calendar year. RESULTS: This analysis included 3907 participants enrolled between April 2019 and April 2022, yielding 3815.7 person-years of follow-up for gonorrhoea (15 134 screenings), 3802.5 for chlamydia (15 141 screenings), and 3858.6 for syphilis (15 001 screenings). The median age was 39 years (interquartile range [IQR] 32-47), 93.8% (n = 3664) identified as men who have sex with men (MSM). The incidence was 22.8 (95% confidence interval [CI] 21.3-24.4) per 100 person-years for gonorrhoea, 26.3 (95% CI 24.7-28.0) for chlamydia, and 4.4 (95% CI 3.8-5.1) for syphilis. Yearly incidence rates decreased between 2019 (all bacterial STIs: 81.6; 95% CI 59.1-109.9) and 2022 (all bacterial STIs: 49.8; 95% CI 44.6-55.3). Participants reporting chemsex substance use were at higher risk of incident STIs, as were those reporting multiple sexual partners. Younger age was associated with a higher risk of gonorrhoea and chlamydia. CONCLUSIONS: Incidence rates of bacterial STIs decreased over time. Young MSM, those with multiple partners, and those using chemsex substances were at increased risk of STIs.

Comparison of the burden of self-reported bacterial sexually transmitted infections among men having sex with men across 68 countries on four continents.

BACKGROUND: Men who have sex with men (MSM) are in general more vulnerable to sexually transmitted infections (STIs) than the heterosexual men population. However, surveillance data on STI diagnoses lack comparability across countries due to differential identification of MSM, diagnostic standards and methods, and screening guidelines for asymptomatic infections. METHODS: We compared self-reported overall diagnostic rates for syphilis, gonorrhea, and chlamydia infections, and diagnostic rates for infections that were classified to be symptomatic in the previous 12 months from two online surveys. They had a shared methodology, were conducted in 68 countries across four continents between October 2017 and May 2018 and had 202,013 participants. RESULTS: Using multivariable multilevel regression analysis, we identified age, settlement size, number of sexual partners, condom use for anal intercourse, testing frequency, sampling rectal mucosa for extragenital testing, HIV diagnosis, and pre-exposure prophylaxis use as individual-level explanatory variables. The national proportions of respondents screened and diagnosed who notified some or all of their sexual partners were used as country-level explanatory variables. Combined, these factors helped to explain differences in self-reported diagnosis rates between countries. The following differences were not explained by the above factors: self-reported syphilis diagnoses were higher in Latin America compared with Europe, Canada, Israel, Lebanon, and the Philippines (aORs 2.30 - 3.71 for symptomatic syphilis compared to Central-West Europe); self-reported gonorrhea diagnoses were lower in Eastern Europe and in Latin America compared with all other regions (aORs 0.17-0.55 and 0.34 - 0.62 for symptomatic gonorrhea compared to Central-West Europe); and self-reported chlamydia diagnoses were lower in Central East and Southeast Europe, South and Central America, and the Philippines (aORs 0.25 - 0.39 for symptomatic chlamydia for Latin American subregions compared to Central West Europe). CONCLUSIONS: Possible reasons for differences in self-reported STI diagnosis prevalence likely include different background prevalence for syphilis and syndromic management without proper diagnosis, and different diagnostic approaches for gonorrhea and chlamydia.

Spatio-temporal changes in pre-exposure prophylaxis uptake among MSM in mainland France between 2016 and 2021: a Bayesian small area approach with MSM population estimation.

INTRODUCTION: In France, oral pre-exposure prophylaxis (PrEP) for HIV prevention has been publicly available since 2016, mainly targeting at men who have sex with men (MSM). Reliable and robust estimations of the actual PrEP uptake among MSM on a localized level can provide additional insights to identify and better reach marginalized MSM within current HIV prevention service provision. This study used national pharmaco-epidemiology surveillance data and regional MSM population estimations to model the spatio-temporal distribution of PrEP uptake among MSM in France 2016-2021 to identify marginalized MSM at risk for HIV and increase their PrEP uptake. METHODS: We first applied Bayesian spatial analyses with survey-surveillance-based HIV incidence data as a spatial proxy to estimate the size of (1) regional HIV-negative MSM populations and (2) MSM who could be eligible for PrEP use according to French PrEP guidelines. We then applied Bayesian spatio-temporal ecological regression modelling to estimate the regional prevalence and relative probability of the overall- and new-PrEP uptake from 2016 to 2021 across France. RESULTS: HIV-negative and PrEP-eligible MSM populations vary regionally across France. Île-de-France was estimated to have the highest MSM density compared to other French regions. According to the final spatio-temporal model, the relative probability of overall PrEP uptake was heterogeneous across France but remained stable over time. Urban areas have higher-than-average probabilities of PrEP uptake. The prevalence of PrEP use increased steadily (ranging from 8.8% [95% credible interval 8.5%;9.0%] in Nouvelle-Aquitaine to 38.2% [36.5%;39.9%] in Centre-Val-de-Loire in 2021). CONCLUSIONS: Our results show that using Bayesian spatial analysis as a novel methodology to estimate the localized HIV-negative MSM population is feasible and applicable. Spatio-temporal models showed that despite the increasing prevalence of PrEP use in all regions, geographical disparities and inequalities of PrEP uptake continued to exist over time. We identified regions that would benefit from greater tailoring and delivery efforts. Based on our findings, public health policies and HIV prevention strategies could be adjusted to better combat HIV infections and to accelerate ending the HIV epidemic.

Association of internalised homonegativity with partner notification after diagnosis of syphilis or gonorrhoea among men having sex with men in 49 countries across four continents.

BACKGROUND: Partner notification (PN) after a sexually transmitted infection (STI) diagnosis is being promoted as a means to interrupt transmission chains. We investigated whether Internalised Homonegativity (IH) is associated with PN among men having sex with men (MSM). METHODS: PN, defined as notifying at least one partner after diagnosis of syphilis and gonorrhoea, was queried in two internet-based self-completion surveys conducted between Oct 2017 and May 2018 in 68 countries in Europe, Latin America, Canada, and the Philippines. IH is defined by a man's level of agreement or disagreement with negative social beliefs about male homosexuality. Covariates included in a multivariate regression model with a random intercept at country level were age, HIV diagnosis, partnership status, sexual self-efficacy, HIV serostatus communication during last sex with a non-steady partner, place where this partner was met, and PN-related socio-historical background of the country of residence. We grouped countries in three areas: North- and Central-Western European countries plus Canada, former socialist countries, and Latin-American/Mediterranean countries plus the Philippines. In each of the three areas individuals were assigned to 4 subgroups based on IH quartiles and PN rates were determined for each subgroup. RESULTS: PN rates were calculated for 49 countries (excluding countries with less than 10 diagnoses). Mean proportions of MSM notifying their partners were 68.1% and 72.9% after syphilis and gonorrhoea diagnoses, respectively. PN rates were lower in Latin American countries and the Philippines compared to European countries. Within Europe, a North-South divide with lower PN rates in Mediterranean countries was observed. In each of the three regions we mostly observed a stepwise increase of PN rates with decreasing IH. Regression analysis showed lower IH scores associated with higher PN rates. Higher perceived self-efficacy, living in a partnership, and HIV status communication were positively associated with PN. Men who had met their last partner in a gay social venue were more likely to have notified their partners of a syphilis diagnosis compared to men who had met this partner online. Men with diagnosed HIV were less likely to report PN. CONCLUSIONS: We could demonstrate that IH was associated with PN among MSM across all countries included in our analysis. Reducing cultural homophobia and ensuring inclusive policies may contribute to STI prevention and control.

Impact of Migration and Acculturation on Turkish Men Who Have Sex with Men in Germany: Results from the 2010 European MSM Internet Survey.

To examine the impact of migration and acculturation of Turkish men who have sex with men (MSM) to Germany, using data from the European MSM Internet Survey (EMIS-2010), on measures of acculturation including circumcision status, internalized homonegativity (IH), HIV/STI knowledge, sexual orientation, outness, HIV-testing, and sexual behaviors. We compared four groups of MSM: MSM born and residing in Germany who had completed the questionnaire in German (n = 38,915), MSM born and residing in Germany, with a father or mother born in Turkey (n = 97), MSM residing in Germany who were born in Turkey or whose parents were born in Turkey (n = 262), and MSM who were born and residing in Turkey and who completed the questionnaire in Turkish (n = 1,717). Data showed that there were significant dose-response curves between level of migration and several outcome variables. As exposure to Germany increased, MSM had lower IH, higher HIV/STI knowledge, increased outness, and were less likely to be circumcised. There were similar significant findings with regard to sexual HIV risk behavior (condomless anal intercourse with partners of unknown (or sero-discordant) HIV status). Data were consistent with acculturation over generations in immigrant groups in MSM migrating from Turkey to Germany. Integration includes both cultural aspects (circumcision) and integration into a more homopositive gay environment (IH, outness, increased HIV/STI knowledge), and sexual HIV risk behavior. Migration and associated acculturation may constitute a risk change for HIV/STI and mental health issues associated with IH and outness.

Latin American Internet Survey for Men who have Sex with Men (LAMIS-2018): Design, methods and implementation.

Despite men-who-have-sex-with-men (MSM) from Latin America (LA) are still a vulnerable population for known health-related conditions and social problems, availability of comparable data across LA countries for assessment and monitoring purposes is limited. The objective of this article is to present the study design and the questionnaire of LAMIS-2018 (Latin America MSM Internet Survey), its recruitment strategy, rates and sources by country, and the lessons learned from its implementation. LAMIS-2018 was a cross-sectional, internet-based survey targeting MSM living in 18 LA countries (Argentina, Bolivia, Brazil, Chile, Colombia, Costa Rica, Ecuador, El Salvador, Guatemala, Honduras, Mexico, Nicaragua, Panama, Paraguay, Peru, Suriname, Uruguay, and Venezuela) that gathered data about sexual behaviors, HIV/STI and viral hepatitis knowledge, prophylactic use of antiretrovirals, psychosocial health, and access to sexual health services. The survey went online for four months and was available in three languages (Spanish, Portuguese, and Dutch). Promotion was carried out using dating apps, websites, social networks, and by community-based and academic organizations of each participating country directly in gay venues and in their own premises. Overall, 64,655 MSM participated in LAMIS-2018. Dating apps and websites were the most important recruitment source in most countries, except for Honduras, Nicaragua, and Suriname, where community-based organizations recruited most of the participants. Beyond the LAMIS-2018 implementation description, we highlight the feasibility of such a study in this context, based on the collaboration between community-based and academic organizations to obtain a large sample of MSM in the region. LAMIS-2018 data will contribute to identify determinants of risk behaviors and prevention needs of vulnerable MSM populations in each country of the region.

Sexual happiness and satisfaction with sexual safety among German trans men who have sex with men: results from EMIS-2017.

INTRODUCTION: The population of men-who-have-sex-with-men (MSM) includes people who are on the masculine spectrum but were assigned female at birth (AFAB), that is trans MSM. This study aims to identify current circumstances regarding sexual happiness and safety among German trans MSM. To date, there is no health information about trans MSM in Germany, limiting the ability of MSM sexual health programmes to meet their needs. METHODS: Data were used from the European MSM Internet Survey (EMIS-2017), where people identifying as men and/or trans men were recruited through dating apps for MSM, community websites and social media to participate in an online survey. We analysed parameters on sexual happiness and satisfaction with sexual safety among Germany-based trans MSM and compared those to outcomes of MSM assigned male at birth (cis MSM) living in Germany using descriptive methods and logistic regression models adjusting for age. RESULTS: In total, 23,001 participants from Germany were included, of which 122 (0.5%) indicated to be AFAB (i.e. trans MSM). Trans MSM were markedly younger than cis participants (median age: 28.5 vs. 39 years). Trans MSM more often reported being unhappy with their current sex life (adjusted odds ratio [aOR] = 1.82, 95% CI 1.24-2.67), had higher odds of disagreeing with the statements "the sex I have is always as safe as I want" ([aOR] = 1.82, 95% CI 1.24-2.67) and "I find it easy to say no to sex that I don't want" ([aOR] = 1.80, 95% CI 1.18-2.77). Trans MSM were more likely to not be living comfortably financially ([aOR] = 2.43, 95% CI 1.60-3.67) and to be living with severe anxiety and/or depression ([aOR] = 3.90, 95% CI 2.22-6.83). Trans MSM were less likely to have ever tested for HIV ([aOR] = 0.63, 95% CI 0.43-0.93). CONCLUSIONS: Sexual happiness, control of sexual boundaries, satisfaction with sexual safety, financial security, mental wellbeing and HIV testing were all lower in German trans MSM compared with cis MSM. Tailored sexual health interventions, contextualized with regard to needs and vulnerabilities, could address this inequality.

[Tick-Borne Encephalitis (TBE) - Fundamentals]. / Frühsommer-Meningoenzephalitis (FSME).

Tick-Borne Encephalitis (TBE) - Fundamentals Abstract. There is widespread endemicity of tick-borne encephalitis (TBE) in all German-speaking countries. In most regions there is a gradual increase in incidence and further territorial spread. As a proportion of the cases is not diagnosed and since the clinical course is getting worse with growing age, substantial underreporting occurs particularly in the pediatric and adolescent patient population. Infected ticks are transmitting the TBE virus, a flavivirus, within a few minutes after the bite. After an incubation period of 4 to 28 days uncharacteristic flu-like symptoms usually occur during a first viremic phase. This is followed by a brief asymptomatic interval before a minority of patients suffer of a variety of symptoms associated with damage of different parts of the central nervous system. This often results in permanent neurological injury and in about 1% the clinical course is fatal. To establish a diagnosis, it is essential to suspect the infection and to obtain a history of exposure. Depending on the phase of illness IgM and/or IgG antibodies can be detected in the serum and/or in the cerebrospinal fluid. In the early phase of the infection the TBE virus may be detected by PCR.

Unsupervised machine learning predicts future sexual behaviour and sexually transmitted infections among HIV-positive men who have sex with men.

Machine learning is increasingly introduced into medical fields, yet there is limited evidence for its benefit over more commonly used statistical methods in epidemiological studies. We introduce an unsupervised machine learning framework for longitudinal features and evaluate it using sexual behaviour data from the last 20 years from over 3'700 participants in the Swiss HIV Cohort Study (SHCS). We use hierarchical clustering to find subgroups of men who have sex with men in the SHCS with similar sexual behaviour up to May 2017, and apply regression to test whether these clusters enhance predictions of sexual behaviour or sexually transmitted diseases (STIs) after May 2017 beyond what can be predicted with conventional parameters. We find that behavioural clusters enhance model performance according to likelihood ratio test, Akaike information criterion and area under the receiver operator characteristic curve for all outcomes studied, and according to Bayesian information criterion for five out of ten outcomes, with particularly good performance for predicting future sexual behaviour and recurrent STIs. We thus assess a methodology that can be used as an alternative means for creating exposure categories from longitudinal data in epidemiological models, and can contribute to the understanding of time-varying risk factors.

Social and behavioural determinants of syphilis: Modelling based on repeated cross-sectional surveys from 2010 and 2017 among 278,256 men who have sex with men in 31 European countries.

Background: Syphilis case notifications among men-who-have-sex-with-men (MSM) have increased markedly over the past two decades in Europe. We tested several potential factors for this resurgence. Methods: Self-reported data from two cross-sectional waves of the European MSM Internet Survey (EMIS-2010 and EMIS-2017, N = 278,256 participants living in 31 European countries) were used to fit multivariable hierarchical logistic regression models designed to evaluate potential social, behavioural, and interventional determinants of syphilis diagnosis. Additional multivariable hierarchical negative binomial models investigated determinants of the number of non-steady male condomless anal intercourse (CAI) partners. We tested the hypothesis that more CAI and syphilis-screening are associated with syphilis resurgence, both linked to use of pre-exposure prophylaxis (PrEP). Findings: Between 2010 and 2017, incidence of syphilis diagnosis in the previous 12 months rose from 2.33% (95%CI: 2.26-2.40) of respondents reporting a syphilis diagnosis in 2010 compared with 4.54% (95%CI: 4.42-4.66) in 2017. Major factors contributing to syphilis diagnosis were living with diagnosed HIV (adjusted odds ratio (aOR) 2.67, 95%CI: 2.32-3.07), each additional non-steady male CAI partner (aOR 1.01, 95%CI: 1.01-1.01), recency of STI-screening (previous month vs no screening, aOR 25.76, 95%CI: 18.23-36.41), selling sex (aOR 1.45, 95%CI: 1.27-1.65), and PrEP use (aOR 3.02, 95%CI: 2.30-3.96). Living with diagnosed HIV (adjusted incidence rate ratio (aIRR) 3.91, 95%CI: 3.77-4.05), selling sex (aIRR 4.39, 95%CI: 4.19-4.59), and PrEP use (aIRR 5.82, 95%CI: 5.29-6.41) were associated with a higher number of non-steady male CAI partners. The association between PrEP use and increased chance of syphilis diagnosis was mediated by STI-screening recency and number of non-steady male CAI partners, both substantially higher in 2017 compared to 2010. Interpretation: Syphilis cases are concentrated in three MSM population groups: HIV-diagnosed, PrEP users, and sex workers. Behavioural and interventional changes, particularly more non-steady male CAI partners and recency of STI-screening, are major contributing factors for increasing syphilis diagnoses among MSM in Europe. Funding: European Centre for Disease Prevention and Control.

Changes in the user profiles of HIV pre-exposure prophylaxis (PrEP) before and after PrEP reimbursement.

BACKGROUND: In Germany, oral HIV pre-exposure prophylaxis (PrEP) was licensed in 2016. Health insurances have been covering the costs since 09/2019. This study compares the sociodemographic profiles of PrEP users before and after PrEP re-imbursement. METHODS: Participants were recruited in a cross-sectoral sexual health centre in Germany. baseline data were compared for 139 vs 138 individuals starting PrEP from 10/2017-12/2018 (pre-reimbursement cohort) and 09/2019-3/2020; respectively. The pre-reimbursement cohort was further analysed with respect to sexual behaviour and incident sexually transmitted infections (STIs). RESULTS: There were no significant differences in the sociodemographic characteristics between the two cohorts. Almost all PrEP users were men-who-have-sex-with-men (MSM). Before reimbursement, fewer individuals used PrEP on a daily base, and more had used PrEP prior to enrolment. During follow-up (pre-reimbursement cohort), the number of sexual and condomless intercourse partners increased, so did the proportion engaging in Chemsex. Incidences of infections with C.trachomatis, N.gonorrhoeae, M.genitalium, and T.pallidum were 45.2; 36.8; 30.1; and 9.2, respectively, per 100 person-years. CONCLUSION: The goal to make PrEP available to a broader range of people with the covering of costs was only partially reached. Medically supervised use is important to detect and treat STIs.

Stigmatizing Policies Interact with Mental Health and Sexual Behaviours to Structurally Induce HIV Diagnoses Among European Men Who Have Sex with Men.

Structural stigma shapes men who have sex with men's (MSM's) mental health and sexual behaviours. The aim of this study was to examine how stigmatizing policies interact with downstream anxiety/depression and sexual behaviours to structurally pattern HIV disparities among European MSM. We conducted a secondary data analysis of the European Men-who-have-sex-with-men Internet Survey (EMIS) from 2017. We included a total of 98,600 participants living in 39 European countries. We used the Rainbow Index, a score given to countries based on their sexual and gender minority policies as the predictor of HIV diagnosis. We conducted adjusted random intercept and slope multi-level logistic regressions. In adjusted models, higher Rainbow Index scores was associated with lower predictive probabilities of diagnosed HIV, regardless of the number of condomless intercourse partners. The predictive probability of HIV diagnosis was also lower, regardless of severity of anxiety/depression, where the Rainbow Index score was better. Country-level policies interact with downstream sexual behaviours and anxiety/depression to structurally influence HIV diagnosis among MSM in Europe.

Retrospective, matched case-control analysis of tickborne encephalitis vaccine effectiveness by booster interval, Switzerland 2006-2020.

OBJECTIVE: To estimate effectiveness of tickborne encephalitis (TBE) vaccination by time interval (<5, 5-10 and 10+years) postvaccination. DESIGN: A retrospective, matched case-control study PARTICIPANTS: Cases-all adult (age 18-79) TBE cases in Switzerland reported via the national mandatory disease reporting surveillance system from 2006 to 2020 (final n=1868). Controls-community controls from a database of randomly selected adults (age 18-79) participating in a 2018 cross-sectional study of TBE vaccination in Switzerland (final n=4625). PRIMARY OUTCOME MEASURES: For cases and controls, the number of TBE vaccine doses received and the time since last vaccination were determined. Individuals were classified as being 'unvaccinated' (0 doses), 'incomplete' (1-2 doses) or 'complete' (3+ doses). Individuals with 'complete' vaccination were further classified by time since the last dose was received (<5 years, 5-10 years or 10+ years). A conditional logistic regression model was used to calculate vaccine effectiveness (VE: 100 × [1-OR]) for each vaccination status category. RESULTS: VE for incomplete vaccination was 76.8% (95% CI 69.0% to 82.6%). For complete vaccination, overall VE was 95.0% (95% CI 93.5% to 96.1%). When the most recent dose was received <5 years prior VE was 91.6% (95% CI 88.4% to 94.0%), 95.2% (95% CI 92.4% to 97.0%) when the most recent dose was received 5-10 years prior, and 98.5% (95% CI 96.8% to 99.2%) when the most recent dose was received 10+ years prior. CONCLUSIONS: That VE does not decrease among completely vaccinated individuals over 10+ years since last vaccination supports the longevity of the protective response following complete TBE vaccination. Our findings support the effectiveness of 10-year TBE booster intervals currently used in Switzerland.

What is the empirical basis for converting banded ordinal data on numbers of sex partners among MSM into a continuous scale level variable? A secondary analysis of 13 surveys across 17 countries.

BACKGROUND: To provide empirically based guidance for substituting partner number categories in large MSM surveys with mean numbers of sexual and condomless anal intercourse (CAI) partners in a secondary analysis of survey data. METHODS: We collated data on numbers of sexual and CAI partners reported in a continuous scale (write-in number) in thirteen MSM surveys on sexual health and behaviour across 17 countries. Pooled descriptive statistics for the number of sexual and CAI partners during the last twelve (N = 55,180) and 6 months (N = 31,759) were calculated for two sets of categories commonly used in reporting numbers of sexual partners in sexual behaviour surveys. RESULTS: The pooled mean number of partners in the previous 12 months for the total sample was 15.8 partners (SD = 36.6), while the median number of partners was 5 (IQR = 2-15). Means for number of partners in the previous 12 months for the first set of categories were: 16.4 for 11-20 partners (SD = 3.3); 27.8 for 21-30 (SD = 2.8); 38.6 for 31-40 (SD = 2.4); 49.6 for 41-50 (SD = 1.5); and 128.2 for 'more than 50' (SD = 98.1). Alternative upper cut-offs: 43.4 for 'more than 10' (SD = 57.7); 65.3 for 'more than 20' (SD = 70.3). Self-reported partner numbers for both time frames consistently exceeded 200 or 300. While there was substantial variation of overall means across surveys, the means for all chosen categories were very similar. Partner numbers above nine mainly clustered at multiples of tens, regardless of the selected time frame. The overall means for CAI partners were lower than those for sexual partners; however, such difference was completely absent from all categories beyond ten sexual and CAI partners. CONCLUSIONS: Clustering of reported partner numbers confirm common MSM sexual behaviour surveys' questionnaire piloting feedback indicating that responses to numbers of sexual partners beyond 10 are best guesses rather than precise counts, but large partner numbers above typical upper cut-offs are common.

Tick-borne encephalitis (TBE) in Switzerland: does the prolongation of vaccine booster intervals result in an increased risk of breakthroughs?

BACKGROUND: In 2006, the Swiss Federal Office of Public Health (FOPH) decided recommending a prolongation of vaccine booster intervals after the third dose for the prevention of tick-borne encephalitis (TBE) from 3 to 10 years. METHODS: To ascertain whether this amendment resulted in an increased rate of vaccine breakthroughs, we conducted a retrospective analysis of surveillance data collected 2000-19 by mandatory reporting to the Swiss FOPH. Fractions of breakthroughs [with 95% confidence intervals (CIs)]-0-3 years vs >3-10 years after the third vaccination dose-were compared across time periods and age groups. RESULTS: Among 3205 notified TBE cases, known vaccination status was reported in 2562 (79.9%), including 103 patients with ≥3 vaccine doses (4.0%). Among those, there were 39 patients who had received the last dose within 3 years and 48 patients in the >3-10 years group. During the 2010-19 period in which the new booster strategy was implemented there were 23 and 38 breakthroughs, respectively, and the annual breakthrough rate was 7.7 (95% CI 5.0-11.7) cases during the first 3 years after the last dose, and 5.4 (95% CI 3.9-7.5) cases in following 7 years. We observed no significant trend of TBE breakthroughs with increasing age. Increasing numbers of TBE and of vaccine breakthroughs over time have been associated with spreading endemicity and higher vaccination coverage in Switzerland. CONCLUSIONS: There is no indication that extended booster intervals resulted in an increased rate of breakthroughs, but there was a marked public health benefit with respect to increased acceptability of TBE immunization in the general population.