HIV testing behaviour and associated factors in men who have sex with men by level of urbanisation : A cross-sectional study in the Netherlands

Acknowledgments We thank Wim Zuilhof, Paul Zantkuijl, Arjan van Bijnen and Koenraad Vermeij from STI AIDS Netherlands for their valuable contribution to the survey Men and Sexuality. In addition, we are grateful to Philippe Adam for making the data available.Peer reviewedPublisher PD

Towards Fully Automated Analysis of Whiteboxes: Perfect Dimensionality Reduction for Perfect Leakage

Differential computation analysis (DCA) is a technique recently introduced by Bos et al. and Sanfelix et al. for key recovery from whitebox implementations of symmetric ciphers. It consists in applying the differential power analysis approach to software execution traces that are obtained by tracing the memory accesses of a whitebox application. While being very effective, DCA relies on analyst intuition to be efficient. In particular, memory range selection is needed to prevent software execution traces from becoming prohibitively long. Moreover, analyst failure to specify the relevant range lets the vulnerable whitebox implementation be evaluated as secure. We present a novel approach for dimensionality reduction of software execution traces, that takes a significant part of analyst intuition out of the loop. The approach exploits the lack of measurement noise in the traces and selects only the samples that are relevant for the key recovery. Our experiments with the published whitebox implementations show that the length of software execution traces can be automatically reduced to a few dozens of bits. This results in an attack speedup of several orders of magnitude, which in turn facilitates the use of more computationally intensive DCA flavours such as multiple leakage targets proposed by Klemsa. Our approach simplifies the methodology for whitebox analysis down to the tracing of a large default memory range, letting our dimensionality reduction techniques extract the relevant points for DCA, and run the attack on multiple leakage targets, excluding analyst errors and saving analysis time. It also provides quick insights in case of whitebox implementations with additional protection layers such as encodings, and can be used to identify the range for fault injection in differential fault analysis. We make our techniques available to the community as a part of a free/libre open-source side channel analysis toolkit. We believe they are a step forward for fully automated whitebox analysis tools

Feasibility of anorectal chlamydia testing in women:a cross-sectional survey among general practitioners

BACKGROUND: Anorectal Chlamydia trachomatis (CT) may be clinically relevant for women in general practice. Although anorectal CT testing in this setting may prevent underdiagnosis and undertreatment, its feasibility is questioned as GPs currently rarely order anorectal CT tests, for yet unknown reasons. OBJECTIVE: To explore the feasibility of anorectal CT testing in women in general practice. METHODS: GPs across the Netherlands were invited directly (n = 1481) and by snowball sampling (n = 330) to join an online cross-sectional survey that asked about the acceptability of and barriers for (standard) anorectal testing in women during CT-related consultations. Data were analysed with univariable and multivariable logistic regression models. RESULTS: The questionnaire was opened by 514 respondents (28%, 514/1811) and 394 fully completed it. GPs' acceptability of anorectal testing by either self-sampling or provider-sampling was high (86%). Twenty-eight percent of GPs felt neutral, and 43% felt accepting towards standard anorectal testing. Nevertheless, 40% of GPs had never tested for anorectal CT in women, which was associated with a reported difficulty in asking about anal sex (odds ratio [OR]: 3.07, 95% confidence interval [CI]: 1.21-7.80), infrequency of anal sexual history taking (OR: 11.50, 95% CI: 6.39-20.72), low frequency of urogenital CT testing (OR 3.44, 95%-CI: 1.86-6.38) and with practicing in a non-urban area (OR: 2.27, 95% CI: 1.48-3.48). Acceptability of anorectal testing was not associated with the studied factors. CONCLUSION: This quantitative survey shows that anorectal CT testing is feasible based on its acceptability, but is likely hindered by a lower awareness of (anorectal) CT in GPs

Symptoms and quality of life before, during, and after a SARS-CoV-2 PCR positive or negative test:data from Lifelines

This study evaluates to what extent symptoms are present before, during, and after a positive SARS-CoV-2 polymerase chain reaction (PCR) test, and to evaluate how the symptom burden and quality of Life (QoL) compares to those with a negative PCR test. Participants from the Dutch Lifelines COVID-19 Cohort Study filled-out as of March 2020 weekly, later bi-weekly and monthly, questions about demographics, COVID-19 diagnosis and severity, QoL, and symptoms. The study population included those with one positive or negative PCR test who filled out two questionnaires before and after the test, resulting in 996 SARS-CoV-2 PCR positive and 3978 negative participants. Nearly all symptoms were more often reported after a positive test versus the period before the test (p &lt; 0.05), except fever. A higher symptom prevalence after versus before a test was also found for nearly all symptoms in negatives (p &lt; 0.05). Before the test, symptoms were already partly present and reporting of nearly all symptoms before did not differ between positives and negatives (p &gt; 0.05). QoL decreased around the test for positives and negatives, with a larger deterioration for positives. Not all symptoms after a positive SARS-CoV-2 PCR test might be attributable to the infection and symptoms were also common in negatives.</p

A Web-Based Respondent Driven Sampling Pilot Targeting Young People at Risk for Chlamydia Trachomatis in Social and Sexual Networks with Testing: A Use Evaluation

YesWith the aim of targeting high-risk hidden heterosexual young people for Chlamydia trachomatis (CT) testing, an innovative web-based screening strategy using Respondent Driven Sampling (RDS) and home-based CT testing, was developed, piloted and evaluated. Two STI clinic nurses encouraged 37 CT positive heterosexual young people (aged 16-25 years), called index clients, to recruit peers from their social and sexual networks using the web-based screening strategy. Eligible peers (young, living in the study area) could request a home-based CT test and recruit other peers. Twelve (40%) index clients recruited 35 peers. Two of these peers recruited other peers (n = 7). In total, 35 recruited peers were eligible for participation; ten of them (29%) requested a test and eight tested. Seven tested for the first time and one (13%) was positive. Most peers were female friends (80%). Nurses were positive about using the strategy. The screening strategy is feasible for targeting the hidden social network. However, uptake among men and recruitment of sex-partners is low and RDS stopped early. Future studies are needed to explore the sustainability, cost-effectiveness, and impact of strategies that target people at risk who are not effectively reached by regular health care

Defining antimicrobial prescribing quality indicators: what is a new prescription?

Contains fulltext : 95791.pdf (publisher's version ) (Open Access): Since guidelines on antibiotic drug treatment often focus on appropriate first choice drugs, assessment of guideline adherence should only concentrate on the first drug prescribed, and not on subsequent antibiotics prescribed after failure of the first one. PURPOSE: To determine a valid cut-off point for a definition of "first" or "new" prescription in indicators for the assessment of the quality of antibiotic drug treatment on the basis of pharmaceutical data. METHODS: Three possible definitions for the term "new prescription" were compared, based on three different periods of time, viz. more than 35, 28, or 21 days after starting a previous antibiotic. In an observational study, 1,225 antimicrobial prescriptions from the medical files of five family practices were audited ("clinical classification") and compared with a classification based on the three definitions ("technical classification"). Agreement between these clinical and technical classifications was determined by calculating Cohen's kappa. The technical classification was analyzed as a diagnostic test, using the clinical classification as the gold standard, and sensitivity, specificity, likelihood ratios, and post-test probabilities were calculated. RESULTS: Defining "new prescription" as "more than 35 days after a previous prescription was issued" resulted in a Cohen's kappa of 0.93 (95% CI 0.92-0.98). The diagnostic value of this definition was extremely high, with a sensitivity of 0.976, specificity of 0.987, positive likelihood ratio of 77.7, and negative likelihood ratio of 0.02. CONCLUSION: We recommend using a cut-off value of 35 days since the last antimicrobial prescription as the definition of a "new prescription" when no diagnostic information is available, i.e., when using pharmaceutical data to assess the quality of antibiotic prescribing behavior.01 januari 201

Newly diagnosed HIV and use of HIV-PrEP among non-western born MSM attending STI clinics in the Netherlands: a large retrospective cohort study

IntroductionThe World Health Organization recommends HIV-PrEP for all people at risk for HIV infection, which includes men who have sex with men (MSM). Substantial part of new HIV diagnoses in the Netherlands are in non-western born MSM. This study evaluated new HIV diagnoses and reported PrEP use among non-western born MSM and compared it to western-born MSM. To inform public health efforts in the context of equitable PrEP access, we further assessed sociodemographic factors related to higher HIV risk and lower PrEP use among non-western born MSM.MethodsSurveillance data of consultations among MSM in all Dutch STI-clinics (2016–2021) were analyzed. STI-clinics provide PrEP via the national pilot-program since August 2019. In non-western born MSM (born in Eastern-Europe/Latin-America/Asia/Africa/Dutch-Antilles/Suriname), sociodemographic factors were evaluated for association with HIV (by multivariable generalized estimating equations) and reported PrEP use in the past 3 months (by multivariable logistic regression; restricted to an at-risk for HIV person-level data-subset from August 2019).ResultsNew HIV infections were diagnosed among 1.1% (493/44,394) of non-western born MSM-consultations (vs. 0.4% among western-born MSM, 742/210,450). Low education (aOR: 2.2, 95%CI: 1.7–2.7, vs. high education) and age under 25 years (aOR: 1.4, 95%CI: 1.1–1.8, vs. age above 35 years) were associated with new HIV diagnoses. PrEP use in the past 3 months was 40.7% in non-western born MSM (1,711/4,207; 34.9% among western-born MSM, 6,089/17,458). PrEP use was lower among non-western born MSM aged under 25 years (aOR: 0.3, 95%CI: 0.2–0.4), living in less urban areas (aOR: 0.7, 95%CI: 0.6–0.8), and having low education level (aOR: 0.6, 95%CI: 0.5–0.7).ConclusionOur study confirmed that non-western born MSM are an important key population in HIV prevention. Access to HIV prevention, including HIV-PrEP, should be further optimized to all non-western born MSM at risk for HIV, and specifically to those who are younger, live in less urban areas, and have a low education level

Social networks in relation to self-reported symptomatic infections in individuals aged 40-75 - the Maastricht study.

Most infections are spread through social networks (detrimental effect). However, social networks may also lower infection acquisition (beneficial effect). This study aimed to examine associations between social network parameters and prevalence of self-reported upper and lower respiratory, gastrointestinal and urinary tract infections in a population aged 40-75