BMJ Open

ObjectivesNeisseria gonorrhoeae (NG) and Chlamydia trachomatis (CT) increase the risk of HIV transmission among men who have sex with men (MSM). Diagnosis of NG/CT may provide an efficient entry point for prevention of HIV through the delivery of pre-exposure prophylaxis (PrEP); however, the additional population-level impact of targeting PrEP to MSM diagnosed with NG/CT is unknown.DesignAn agent-based simulation model of NG/CT and HIV cocirculation among MSM calibrated against census data, disease surveillance reports and the US National HIV Behavioral Surveillance study.SettingBaltimore City, Maryland, USA.InterventionsPrEP implementation was modelled under three alternative scenarios: (1) PrEP delivery at NG/CT diagnosis (targeted delivery), (2) PrEP evaluation at NG/CT screening/testing and (3) PrEP evaluation in the general community (untargeted).Main outcomeThe projected incidence of HIV after 20 years of PrEP delivery under two alternatives: when equal numbers of MSM are (1) screened for PrEP or (2) receive PrEP in each year.ResultsAssuming 60% uptake and 60% adherence, targeting PrEP to MSM diagnosed with NG/CT could reduce HIV incidence among MSM in Baltimore City by 12.4% (95% uncertainty range (UR) 10.3% to 14.4%) in 20 years, relative to no PrEP. Expanding the coverage of NG/CT screening (such that individuals experience a 50% annual probability of NG/CT screening and evaluation for PrEP on NG/CT diagnosis) can further increase the impact of targeted PrEP to generate a 22.0% (95% UR 20.1% to 23.9%) reduction in HIV incidence within 20 years. When compared with alternative implementation scenarios, PrEP evaluation at NG/CT diagnosis increased impact of PrEP on HIV incidence by 1.5(95% UR 1.1 to 1.9) times relative to a scenario in which PrEP evaluation happened at the time of NG/CT screening/testing and by 1.6 (95% UR 1.2 to 2.2) times relative to evaluating random MSM from the community.ConclusionsTargeting MSM infected with NG/CT increases the efficiency and effectiveness of PrEP delivery. If high levels of sexually transmitted infection screening can be achieved at the community level, NG/CT diagnosis may be a highly effective entry point for PrEP initialisation.30837248PMC6429744619

Developing service supply chains by using agent based simulation

The Master thesis present a novel approach to model a service supply chain with agent based simulation. Also, the case study of thesis is related to healthcare services and research problem includes facility location of healthcare centers in Vaasa region by considering the demand, resource units and service quality. Geographical information system is utilized for locating population, agent based simulation for patients and their illness status probability, and discrete event simulation for healthcare services modelling. Health centers are located on predefined sites based on managers’ preference, then each patient based on the distance to health centers, move to the nearest point for receiving the healthcare services. For evaluating cost and services condition, various key performance indicators have defined in the modelling such as Number of patient in queue, patients waiting time, resource utilization, and number of patients ratio yielded by different of inflow and outflow. Healthcare managers would be able to experiment different scenarios based on changing number of resource units or location of healthcare centers, and subsequently evaluate the results without necessity of implementation in real life.fi=Opinnäytetyö kokotekstinä PDF-muodossa.|en=Thesis fulltext in PDF format.|sv=Lärdomsprov tillgängligt som fulltext i PDF-format

TARGETED HIV AND STI SCREENING STRATEGIES AMONGST MSM IN BALTIMORE, AND THE IMPACT ON THE HIV EPIDEMIC: Using Agent Based Models to Study STI- HIV Co-infection Dynamics

Co-infection of men who have sex with men who have sex with men (MSM) with HIV and and Neisseria gonorrhoeae/Chlamydia trachomatis (NG/CT) remains a significant public health problem in the United States due to co-infection dynamics creating an epidemiologic phenomenon whereby co-epidemics of HIV and NG/CT (along with other STIs) help propagate each other. One of the key components of the US National AIDS Strategy revolves around the HIV Care Continuum, in which HIV-infected persons are diagnosed, linked to care, retained in care and virally suppressed to prevent transmission. Screening for HIV is the entry point for the care continuum and various understanding the most efficacious strategies for this is of utmost importance to help identify HIV-infected persons and link them to care. We used an agent-based model to test three screening strategies for efficacy: targeting high-risk MSM, increased general HIV screening, and improved NG/CT screening amongst HIV-infected MSM. Targeting high-risk MSM and increased general HIV screening produced significant decreases in the HIV and NG/CT incidence relative to baseline, but the former produced steeper declines while simultaneously testing thousands less persons. Improved NG/CT screening amongst HIV-infected MSM has no impact on the incidence rate of either. The targeting high-risk MSM strategy produced steep declines in HIV incidence, and efficiently achieved this in less HIV tests given per year compared to the general HIV screening. This suggests that targeting high-risk MSM may be a more effective approach to achieve a reduction in HIV incidence. Furthermore, it suggests that the HIV epidemic amongst MSM in Baltimore may be concentrated amongst a subset of the MSM population