• Cost-effectiveness of increased hiv testing among MSM in the netherlands.

      Reitsema, Maarten; Steffers, Linda; Visser, Maartje; Heijne, Janneke; Hoek, Albert Jan Van; Loeff, Maarten Schim Van Der; van Sighem, Ard; van Benthem, Birgit; Wallinga, Jacco; Xiridou, Maria; et al. (2019-03-15)
      To assess the cost-effectiveness of increased consistent HIV testing among men who have sex with men (MSM) in the Netherlands. Among MSM testing at STI clinics in the Netherlands in 2014-2015, approximately 20% tested consistently every six months. We examined four scenarios with increased percentage of MSM testing every six months: a small and a moderate increase among all MSM; a small and a moderate increase only among MSM with ≥10 partners in the preceding six months. We used an agent-based model to calculate numbers of HIV infections and AIDS cases prevented with increased HIV testing. These numbers were used in an economic model to calculate costs, quality-adjusted life-years (QALY), and incremental cost-effectiveness ratios (ICER) due to increased testing, over 2018-2027, taking a healthcare payer perspective. A small increase in the percentage testing every six months among all MSM resulted in 490 averted HIV infections and an average ICER of &OV0556;27,900/QALY gained. A moderate increase among all MSM, resulted in 1380 averted HIV infections and an average ICER of &OV0556;36,700/QALY gained. Both were not cost-effective, with a &OV0556;20,000 willingness-to-pay threshold. Increasing the percentage testing every six months only among MSM with ≥10 partners in the preceding six months resulted in less averted HIV infections than increased testing among all MSM, but was on average cost-saving. Increased HIV testing can prevent considerable numbers of new HIV infections among MSM, but may be cost-effective only if targeted at high-risk individuals, such as those with many partners.
    • Ending risk-group HBV vaccination for MSM after the introduction of universal infant HBV vaccination: A mathematical modelling study.

      Xiridou, Maria; Visser, Maartje; Urbanus, Anouk; Matser, Amy; van Benthem, Birgit; Veldhuijzen, Irene (2021-04-22)
    • Impact of frequent testing on the transmission of HIV and among men who have sex with men: a mathematical modelling study.

      Reitsema, Maarten; Heijne, Janneke; Visser, Maartje; van Sighem, Ard; Schim van der Loeff, Maarten; Op de Coul, Eline L M; Bezemer, Daniela; Wallinga, Jacco; van Benthem, Birgit H B; Xiridou, Maria (2020-08-01)
      We developed an agent-based transmission model that simulates infection with HIV or Neisseria gonorrhoeae (NG) among MSM. We examined scenarios with increased percentages of MSM getting tested six monthly, among all MSM or only specific subgroups of MSM (defined according to recent gonorrhoea, number of partners and engagement in condomless anal intercourse (CAI)) and scenarios with reduced intervals between HIV/STI tests.
    • Impact of point-of-care management on the transmission of anogenital gonococcal infections among men who have sex with men in Amsterdam: a mathematical modelling and cost-effectiveness study.

      Bartelsman, Menne; Vaughan, Kelsey; van Rooijen, Martijn S; de Vries, Henry J C; Xiridou, Maria (2017-09-23)
      Point-of-care (POC) management may avert ongoing transmissions occurring between testing and treatment or due to loss to follow-up. We modelled the impact of POC management of anogenital gonorrhoea (with light microscopic evaluation of Gram stained smears) among men who have sex with men (MSM) on gonorrhoea prevalence and testing and treatment costs.
    • Microscopic examination of Gram-stained smears for anogenital gonorrhoea in men who have sex with men is cost-effective: evidence from a modelling study.

      Zwart, Jolijn M; Mangen, Marie-Josee J; Bartelsman, Menne; van Rooijen, Martijn S; de Vries, Henry J C; Xiridou, Maria (2018-09-08)
      To assess the cost-effectiveness of three testing strategies with or without light microscopic Gram-stained smear (GSS) evaluation for the detection of anogenital gonorrhoea among men who have sex with men (MSM) at the Amsterdam STI clinic using a healthcare payer perspective.
    • Offering a choice of daily and event-driven preexposure prophylaxis for men who have sex with men in the Netherlands: a cost-effectiveness analysis.

      van Hoek, Albert Jan; Reitsema, Maarten; Xiridou, Maria; van Sighem, Ard; van Benthem, Birgit; Wallinga, Jacco; van Duijnhoven, Yvonne; van der Loeff, Maarten Schim; Prins, Maria; Hoornenborg, Elske
    • Potential effectiveness of prophylactic HPV immunization for men who have sex with men in the Netherlands: A multi-model approach.

      Bogaards, Johannes A; Mooij, Sofie H; Xiridou, Maria; Schim van der Loeff, Maarten F (2019-03-01)
      Men who have sex with men (MSM) are at high risk for anal cancer, primarily related to human papillomavirus genotype 16 (HPV16) infections. At 8.5 per 100,000 per year, the incidence rate of anal cancer among MSM is similar to that of cervical cancer among adult women in the Netherlands. However, MSM are not included in most HPV vaccination programs. We explored the potential effectiveness of prophylactic immunization in reducing anogenital HPV16 transmission among MSM in the Netherlands. We developed a range of mathematical models for penile-anal HPV16 transmission, varying in sexual contact structure and natural history of infection, to provide robust and plausible predictions about the effectiveness of targeted vaccination. Models were informed by an observational cohort study among MSM in Amsterdam, 2010-2013. Parameters on sexual behavior and HPV16 infections were obtained by fitting the models to data from 461 HIV-negative study participants, considered representative of the local MSM population. We assumed 85% efficacy of vaccination against future HPV16 infections as reported for HIV-negative MSM, and age-specific uptake rates similar to those for hepatitis B vaccination among MSM in the Netherlands. Targeted vaccination was contrasted with vaccination of 12-year-old boys at 40% uptake in base-case scenarios, and we also considered the effectiveness of a combined strategy. Offering vaccine to MSM without age restrictions resulted in a model-averaged 27.3% reduction (90% prediction interval [PI] 11.9%-37.5%) in prevalence of anal HPV16 infections, assuming similar uptake among MSM as achieved for hepatitis B vaccination. The predicted reduction improved to 46.1% (90% PI 21.8%-62.4%) if uptake rates among MSM were doubled. The reductions in HPV16 infection prevalence were mostly achieved within 30 years of a targeted immunization campaign, during which they exceeded those induced by vaccinating 40% of preadolescent boys, if started simultaneously. The reduction in anal HPV16 prevalence amounted to 74.8% (90% PI 59.8%-93.0%) under a combined vaccination strategy. HPV16 prevalence reductions mostly exceeded vaccine coverage projections among MSM, illustrating the efficiency of prophylactic immunization even when the HPV vaccine is given after sexual debut. Mode of protection was identified as the key limitation to potential effectiveness of targeted vaccination, as the projected reductions were strongly reduced if we assumed no protection against future infections in recipients with prevalent infection or infection-derived immunity at the time of immunization. Unverified limitations of our study include the sparsity of data to inform the models, the omission of oral sex in transmission to the penile or anal site, and the restriction that our modeling results apply primarily to HIV-negative MSM. Our findings suggest that targeted vaccination may generate considerable reductions in anogenital HPV16 infections among MSM, and has the potential to accelerate anal cancer prevention, especially when combined with sex-neutral vaccination in preadolescence.
    • Preexposure prophylaxis for men who have sex with men in the Netherlands: impact on HIV and Neisseria gonorrhoeae transmission and cost-effectiveness.

      Reitsema, Maarten; Hoek, Albert Jan Van; van der Loeff, Maarten Schim; Hoornenborg, Elske; van Sighem, Ard; Wallinga, Jacco; van Benthem, Birgit; Xiridou, Maria (2020-03-15)