Viability assessment of Chlamydia trachomatis in men who have sex with men using molecular and culture methods.

Objectives: Chlamydia trachomatis is the most commonly diagnosed bacterial sexually transmitted infection (STI) worldwide. Diagnosis relies on nucleic acid amplification techniques, such as PCR, which does not distinguish between viable pathogens and residual bacterial DNA, leading to potential overdiagnosis and overtreatment. PCR with confirmation of pathogen viability has not been widely explored in the STI field.

Sexual behaviours and risk of SARS-CoV-2 infection among MSM during the first COVID-19 lockdown.

Background: The social distancing measures associated with the COVID-19 pandemic had far reaching effects on sexual behavior worldwide. However, it remains unclear whether sexual contact with non-steady partners was a contributor to the spread of SARS-CoV-2. The aim of this study was to (i) describe risk factors for SARS-CoV-2 seropositivity after the first pandemic wave among people using HIV Pre-Exposure Prophylaxis (PrEP) in Zurich, Switzerland, including sexual contact with non-steady partners, and (ii) assess whether the SARS-CoV-2 seropositivity among PrEP users in this time period differed from that of a demographic matched population level comparison group.

Cohort Profile: The Zurich Primary HIV Infection Study.

The Zurich Primary HIV Infection (ZPHI) study is a longitudinal cohort study established in 2002, aiming to study the clinical, epidemiological, and biological characteristics of primary HIV infection. The ZPHI enrolls individuals with documented primary HIV-1 infection. At the baseline and thereafter, the socio-demographic, clinical, and laboratory data are systematically collected, and regular blood sampling is performed for biobanking.

Phenotypic and genotypic characterization of isolates among individuals at high risk for sexually transmitted diseases in Zurich, Switzerland.

Background: While ceftriaxone resistance remains scarce in Switzerland, global (NG) antimicrobial resistance poses an urgent threat. This study describes clinical characteristics in MSM (men who have sex with men) diagnosed with NG infection and analyses NG resistance by phenotypic and genotypic means.

Methods: Data of MSM enrolled in three clinical cohorts with a positive polymerase chain reaction test (PCR) for NG were analysed between January 2019 and December 2021 and linked with antibiotic susceptibility testing.

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.

Sustained Viral Suppression With Dolutegravir Monotherapy Over 192 Weeks in Patients Starting Combination Antiretroviral Therapy During Primary Human Immunodeficiency Virus Infection (EARLY-SIMPLIFIED): A Randomized, Controlled, Multi-site, Noninferiority Trial.

Background: Starting combination antiretroviral therapy (cART) during primary human immunodeficiency virus type 1 (HIV-1) infection results in a smaller HIV-1 latent reservoir, reduced immune activation, and less viral diversity compared to starting cART during chronic infection. We report results of a 4-year study designed to determine whether these properties would allow sustained virological suppression after simplification of cART to dolutegravir (DTG) monotherapy.

Methods: EARLY-SIMPLIFIED is a randomized, open-label, noninferiority trial.

Risk Factors and Incidence of Sexually Transmitted Infections in the Swiss HIV Cohort Study.

Background: Sexually transmitted infections (STIs) are common among people with human immunodeficiency virus (PWH), but there are limited data about risk factors and incidence of STIs in large, representative cohort studies.

Methods: We assessed incidence and risk factors of STIs reported by treating physicians within the Swiss HIV Cohort Study (SHCS). Sexually transmitted infections and demographic, clinical, and behavioral characteristics were prospectively collected at 6-month follow-up visits between October 2017 and November 2019.

Changes in mental and sexual health among MSM using HIV pre-exposure prophylaxis during the SARS-CoV-2 pandemic: longitudinal analysis of the SwissPrEPared cohort study.

Background: Changes in mental and sexual health among men having sex with men (MSM) due to the SARS-CoV-2 pandemic remain unclear.

Methods: Design: Longitudinal analysis of an ongoing, multicentre, pre-exposure prophylaxis (PrEP) cohort (NCT03893188) in Switzerland. Participants: HIV-negative MSM aged ≥18 who completed at least one questionnaire before and one after the start of the SARS-CoV-2 pandemic.

Identifying and Characterizing Trans Women in the Swiss HIV Cohort Study as an Epidemiologically Distinct Risk Group.

Background: As trans women are disproportionately affected by the HIV epidemic, and are still understudied, we aimed to identify and characterize the trans women in the Swiss HIV Cohort Study (SHCS).

Methods: A combination of criteria from pre-existing cohort data was used to identify trans women. Information on socioeconomic factors, clinical data, risk behaviors, and mental health was collected.

Quantitative modeling predicts mechanistic links between pre-treatment microbiome composition and metronidazole efficacy in bacterial vaginosis.

Bacterial vaginosis is a condition associated with adverse reproductive outcomes and characterized by a shift from a Lactobacillus-dominant vaginal microbiota to a polymicrobial microbiota, consistently colonized by strains of Gardnerella vaginalis. Metronidazole is the first-line treatment; however, treatment failure and recurrence rates remain high. To understand complex interactions between Gardnerella vaginalis and Lactobacillus involved in efficacy, here we develop an ordinary differential equation model that predicts bacterial growth as a function of metronidazole uptake, sensitivity, and metabolism.

A Treatment-as-Prevention Trial to Eliminate Hepatitis C Among Men Who Have Sex With Men Living With Human Immunodeficiency Virus (HIV) in the Swiss HIV Cohort Study.

Background: In 2016, the World Health Organization (WHO) introduced global targets for the elimination of hepatitis C virus (HCV) by 2030. We conducted a nationwide HCV micro-elimination program among men who have sex with men (MSM) living with human immunodeficiency virus (HIV) from the Swiss HIV Cohort Study (SHCS) to test whether the WHO goals are achievable in this population.

Methods: During phase A (10/2015-06/2016), we performed a population-based and systematic screening for HCV-RNA among MSM from the SHCS.

A Systematic Phylogenetic Approach to Study the Interaction of HIV-1 With Coinfections, Noncommunicable Diseases, and Opportunistic Diseases.

To systematically test whether coinfections spread along the HIV-1 transmission network and whether similarities in HIV-1 genomes predict AIDS-defining illnesses and comorbidities, we analyzed the distribution of these variables on the HIV phylogeny of the densely sampled Swiss HIV Cohort Study. By combining different statistical methods, we could detect, quantify, and explain the clustering of diseases. Infectious conditions such as hepatitis C, but also Kaposi sarcoma, clustered significantly, suggesting transmission of these infections along the HIV-1 transmission network.

Noninferiority of Simplified Dolutegravir Monotherapy Compared to Continued Combination Antiretroviral Therapy That Was Initiated During Primary Human Immunodeficiency Virus Infection: A Randomized, Controlled, Multisite, Open-label, Noninferiority Trial.

Background: Patients who start combination antiretroviral therapy (cART) during primary human immunodeficiency virus type 1 (HIV-1) infection show a smaller HIV-1 latent reservoir, less immune activation, and less viral diversity compared to patients who start cART during chronic infection. We conducted a pilot study to determine whether these properties would allow sustained virological suppression after simplification of cART to dolutegravir monotherapy.

Methods: EARLY-SIMPLIFIED is a randomized, open-label, noninferiority trial.

High Number of Potential Transmitters Revealed in a Population-based Systematic Hepatitis C Virus RNA Screening Among Human Immunodeficiency Virus-infected Men Who Have Sex With Men.

Background: The proportion of undiagnosed hepatitis C virus (HCV) infections in high-risk populations, such as human immunodeficiency virus (HIV)-infected men who have sex with men (MSM) is unclear. Identification of potential HCV transmitters is important to reach World Health Organization HCV elimination targets.

Methods: Between October 2015 and May 2016, we performed a systematic HCV RNA-based screening among HIV-infected MSM participating in the Swiss HIV Cohort Study (SHCS).

High Cure Rates With Grazoprevir-Elbasvir With or Without Ribavirin Guided by Genotypic Resistance Testing Among Human Immunodeficiency Virus/Hepatitis C Virus-coinfected Men Who Have Sex With Men.

Background: This study was performed to investigate the efficacy and safety of grazoprevir-elbasvir guided by baseline resistance-associated substitutions (RASs) in the Swiss HCVree Trial.

Methods: We performed hepatitis C virus (HCV) RNA screening among all men who have sex with men (MSM) enrolled in the Swiss HIV Cohort Study. Individuals with replicating HCV genotype 1 or 4 infection were eligible for grazoprevir-elbasvir treatment.