Publications by authors named "Maarten F Schim Van Der Loeff"

Background: People with HIV (PWH) experience a higher burden of ageing-associated comorbidities, the underlying mechanisms of which remain to be fully elucidated. We aimed to identify profiles based on immune, inflammatory, and ageing biomarkers in blood from PWH and controls, and explore their association with total comorbidities over time.

Methods: Latent profile analysis was used to construct biomarker profiles in AGEhIV cohort participants (94 with well-controlled HIV on antiretroviral therapy (ART) and 95 controls without HIV) using baseline measurements of selected biomarkers.

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Objective: Various European countries noted increasing (Ng) positivity among cis-gender women and heterosexual men. We assessed changes over time in Ng among men who exclusively have sex with men (MSM), men who exclusively have sex with women (MSW), men who have sex with men and women (MSMW), women and transgender and gender diverse people (TGP).

Methods: We analysed data collected between 2018 and 2023 at the Centre for Sexual Health, Amsterdam.

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Objective: HIV can be effectively prevented by oral HIV pre-exposure prophylaxis (PrEP). When PrEP was introduced, there was apprehension that condom use would decrease and STIs would increase. The purpose of this study was to investigate sexual behaviour and STI incidence among PrEP users.

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  • * A study involving 4,488 young women assessed the vaccine's effectiveness against specific HPV types, finding high efficacy rates of 93.5% for HPV-16 and 89.5% for HPV-18, with additional cross-protection against other types.
  • * Results showed that the vaccine's effectiveness was similar for women who participated in catch-up vaccinations compared to those who received routine vaccinations, indicating both approaches are equally effective.
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Objective: The Dutch HIV preexposure prophylaxis (PrEP) pilot provided subsidized PrEP care to maximum 2900 individuals at a time in Amsterdam. Populations with expected barriers to accessing PrEP elsewhere were prioritized for program inclusion. We evaluated their prior sexual health service engagement and PrEP need.

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  • Enteric hepatitis A virus (HAV) often goes unnoticed in children but can severely affect adults; the study aimed to improve surveillance during an outbreak at a primary school.
  • Researchers used passive samplers in sewage to detect HAV RNA from November 2022 to March 2023, finding that 25% of samples tested positive and matched the strain from the symptomatic cases.
  • The study concludes that sewage monitoring with passive samplers is an effective tool for quickly detecting HAV, identifying unnoticed infections, and enhancing public health responses during outbreaks.
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  • From 2009 to 2021, the Netherlands only offered bivalent HPV vaccination to girls, prompting an investigation into its effects on genital HPV prevalence among young adults.
  • Data were collected through a study called PASSYON, which involved sexual health clinic clients aged 16-24, revealing significant declines in certain high-risk HPV types amongst vaccinated and unvaccinated females over time.
  • The study highlighted successful herd protection effects of the vaccination for heterosexual males and unvaccinated females, while also indicating concerning trends of increasing HPV types related to vaccine phylogeny, suggesting potential type-replacement issues.
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Background: Little is known about the risk of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron infection in people with human immunodeficiency virus (HIV; PWH) with vaccine-induced or hybrid immunity. We assessed the incidence of Omicron infection in 209 AGEIV coronavirus disease 2019 substudy participants with well-controlled HIV on antiretroviral therapy and 280 comparable controls, who had received at least the primary vaccination series.

Methods: From September 2020 onward, participants were assessed every 6 months for the incidence of SARS-CoV-2 infection, per SARS-CoV-2 nucleocapsid antibody assay or self-reported positive antigen or polymerase chain reaction test.

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Introduction: Syphilis incidence is rising among gay, bisexual and other men who have sex with men (GBMSM). To improve early health-seeking behaviour, we developed an online syphilis symptom score tool for GBMSM to self-identify a higher likelihood of infectious syphilis and promoted its use via an online and offline awareness campaign.

Methods: From October 2018 through September 2019, a dedicated website on syphilis including the online symptom score tool was promoted.

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Objectives: This study aimed to assess associations of potential risk factors with human papillomavirus (HPV) seropositivity among men who have sex with men (MSM) and compare these to risk factors for anal and penile (HPV) deoxyribonucleic acid (DNA)-positivity in the same study population.

Methods: Seropositivity and anal and penile HPV DNA-positivity were determined for seven high-risk HPV genotypes for MSM aged 16-24 years participating in Papillomavirus Surveillance among STI clinic Youngsters in the Netherlands (PASSYON) 2009-2021. Logistic regression models were conducted to assess risk factors for seropositivity, anal and penile HPV DNA-positivity.

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Background: An increasing number of countries are currently implementing or scaling-up HIV pre-exposure prophylaxis (PrEP) care. With the introduction of PrEP, there was apprehension that condom use would decline and sexually transmitted infections (STIs) would increase. To inform sexual health counselling and STI screening programmes, we aimed to study sexual behaviour and STI incidence among men who have sex with men (MSM) and transgender women who use long-term daily or event-driven PrEP.

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Objective: We assessed the association and concordance between self-reported oral pre-exposure prophylaxis (PrEP) intake in a diary app and intraerythrocytic drug metabolite concentrations.

Design: AMPrEP was a prospective demonstration study providing daily and event-driven PrEP to MSM in Amsterdam, the Netherlands (2015-2020).

Methods: Participants could record their PrEP intake in a diary app.

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Objective: Ethnic minority groups have experienced a disproportionate burden of COVID-19, and should therefore be especially encouraged to receive SARS-CoV-2 vaccination. This study compared first-dose uptake of the primary SARS-CoV-2 vaccination series across six ethnic groups in Amsterdam, the Netherlands in 2021.

Methods: We analyzed data from participants of the population-based HELIUS cohort.

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Background: In response to the mpox outbreak, vaccination was offered in the Netherlands to men who have sex with men (MSM) at increased risk for mpox. Successful vaccination campaigns are leveraged by high intent-to-vaccinate, yet intent might not always lead to uptake. Therefore, we assessed the impact of intent-to-vaccinate and other factors on vaccination uptake among participants of the Amsterdam Cohort Studies (ACS).

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Background: Daily and event-driven HIV pre-exposure prophylaxis (PrEP) with oral tenofovir-emtricitabine is highly effective to prevent HIV in men who have sex with men (MSM). PrEP care generally consists of in-clinic monitoring every 3 months that includes PrEP dispensing, counseling, and screening for HIV and sexually transmitted infections (STIs). However, the optimal frequency for monitoring remains undetermined.

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  • Antiretroviral therapy (ART) has improved lifespans for people with HIV (PWH), but they face increased inflammation-related health issues due to changes in the gut microbiome.
  • The study reveals that ART-treated PWH have lower levels of beneficial gut bacteria that produce short-chain fatty acids (SCFAs), which help fight inflammation; even though SCFA levels in feces seem normal, serum levels are actually reduced and correlate with inflammation markers.
  • Findings indicate that microbiome changes linked to HIV occur before the onset of health complications, specifically the reduced ability to convert lactate to propionate, suggesting that gut health may play a crucial role in managing HIV-related health risks.
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A growing proportion of head and neck cancer (HNC), especially oropharyngeal cancer (OPC), is caused by human papillomavirus (HPV). There are several markers for HPV-driven HNC, one being HPV early antigen serology. We aimed to investigate the diagnostic accuracy of HPV serology and its performance across patient characteristics.

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Objective: Studies have shown varying trends in incidence of sexually transmitted infections (STIs) among individuals using HIV pre-exposure prophylaxis (PrEP). Characterization of individuals at increased risk for STIs may offer an opportunity for targeted STI screening.

Design: Group-based trajectory modeling.

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Background: We assessed the association between sexualized drug use (SDU), and incident sexually transmitted diseases (STDs) and human immunodeficiency virus (HIV) infections among men who have sex with men (MSM).

Methods: We used data from the MS2 cohort study, conducted at the STI Outpatient Clinic of the Public Health Service of Amsterdam, the Netherlands, in 2014-2019. Eligible participants were adult HIV-negative MSM with ≥2 STDs in the preceding year and MSM living with HIV and ≥1 STD.

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  • Adherence to daily PrEP is crucial for its effectiveness in preventing HIV, and this study focused on identifying factors that influence adherence among men who have sex with men (MSM).
  • Researchers analyzed dried blood spots (DBS) from 263 participants at 12 and 24 months to measure tenofovir diphosphate (TFV-DP) concentrations, using multivariable regression to link sociodemographic and behavioral traits to adherence levels.
  • Results showed high TFV-DP concentrations (indicating good adherence), particularly among older men, those who had condomless sex with casual partners before starting PrEP, and users of an app that tracks their PrEP use, while longer PrEP duration was associated with
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Few studies have comprehensively compared severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine-induced and hybrid B- and T-cell responses in people with HIV (PWH) to those in comparable controls without HIV. We included 195 PWH and 246 comparable controls from the AGEIV COVID-19 substudy. A positive nucleocapsid antibody (INgezim IgA/IgM/IgG) or self-reported PCR test defined prior SARS-CoV-2 infection.

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Background: Knowledge on genital type-specific human papillomavirus (HPV) prevalence among men is important for prevention of HPV-related cancers and other diseases. Men who have sex with men (MSM) have higher anal prevalence than men who have sex with women only (MSW) but for genital HPV this is unclear. We performed a systematic review and meta-analysis of type-specific genital HPV prevalence among men, by sexual orientation.

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Background: People with HIV generally have more ageing-associated comorbidities than those without HIV. We aimed to establish whether the difference in comorbidities and their disease burden changes with ageing.

Methods: In this prospective, longitudinal cohort study, we assessed comorbidities commonly associated with ageing every 2 years in 596 HIV-positive and 550 HIV-negative participants.

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