• Waning and boosting: on the dynamics of immune status.

      Diekmann, O; de Graaf, W F; Kretzschmar, M E E; Teunis, P F M (2018-05-15)
      The aim is to describe the distribution of immune status (as captured by antibody level) on the basis of a within-host submodel for continuous waning and occasional boosting. Inspired by Feller's fundamental work and the more recent delay equation formulation of models for the dynamics of physiologically structured populations, we derive, for given force of infection, a linear renewal equation. The solution is obtained by generation expansion, with the generation number corresponding to the number of times the individual became infected. Our main result provides a precise characterization of the stable distribution of immune status.
    • Weather correlates of Campylobacter prevalence in broilers at slaughter under tropical conditions in Sri Lanka.

      Kalupahana, R S; Mughini-Gras, L; Kottawatta, S A; Somarathne, S; Gamage, C; Wagenaar, J A (2018-04-15)
      Campylobacter is the primary agent of human bacterial gastroenteritis worldwide. In contrast to temperate zones, weather effects on Campylobacter prevalence in broilers under tropical conditions are under-researched. We examined the association between weather and Campylobacter prevalence in slaughtered broilers in Sri Lanka, a tropical country with weather variations led by monsoons. Each month (October 2009-July 2011), 20-30 broiler batches referring to two semi-automated slaughterhouses from five Sri Lankan provinces were tested for Campylobacter contamination and analysed in relation to temperature, humidity and rainfall. Overall prevalence was 63.8% (95% CI 59.6-67.9%, n = 542), peaking in September-November. Each 1 °C increase in monthly mean temperature up to 26 °C increased Campylobacter-positive batches by 16.4% (95% CI 0.4-35.1%). For each 10 mm increase in monthly total rainfall up to 300 mm, Campylobacter-positive batches increased significantly by 0.8% (0.1-1.5%) at 1-month lag. For each 1% increase in relative humidity up to 80% at 1- and 2-month lags, Campylobacter-positive batches increased of respectively 4.2% (1.9-6.7%) and 4.0% (1.5-6.5), and decreased by 3.6% (2.6-4.6%) and 4.0% (2.6-5.4%) for unit increases above 80%. These results suggest that even in tropical countries without marked seasons, there are weather effects possibly reflecting Campylobacter potential to colonise its preferred host and/or survive in the environment.
    • Werknemers en kinkhoest: criteria voor vaccinatie

      Meerstadt F; Maas J; Ruijs H; van Vliet H (2018-04)
    • WGS more accurately predicts susceptibility of Mycobacterium tuberculosis to first-line drugs than phenotypic testing.

      Jajou, Rana; van der Laan, Tridia; de Zwaan, Rina; Kamst, Miranda; Mulder, Arnout; de Neeling, Albert; Anthony, Richard; van Soolingen, Dick (2019-05-22)
    • What benefits and harms are important for a decision about cervical screening? A study of the perspective of different subgroups of women.

      van der Meij, Amber E; Damman, Olga C; Uiters, Ellen; Timmermans, Danielle Rm (2019-01-01)
      Background: In cervical screening programs, women typically receive information leaflets to support their decision about participation. However, these leaflets are often based on what experts consider important benefits and harms of screening and not what women themselves consider important to know. Objective: To identify which benefits and harms women consider important for making a decision about cervical screening. Design: Cross-sectional study. Setting and participants: Women from the Dutch target group of cervical screening (N=248; 30-60 years), recruited through an online access panel. Main variables studied: Perceived importance of different benefits and harms of cervical screening, assessed through two rating items ("How important is the information about [this harm/benefit] for your decision?" and "For me it is a [benefit/harm] that participating in the screening program leads to [the benefit/harm]"), and one ranking item ("Rank the information according to their importance for your own choice"). Results: Women overall considered the benefits of cervical screening more important than the harms or disadvantages. The most important harm according to women was the chance of false positive results (M=4.88; SD=1.75). Differences between those with lower and higher numeracy/health literacy were found regarding several aspects, e.g. for the chance of false positive results, the chance of false negative results, the chance of overtreatment. Discussion and conclusion: The results suggest that leaflets could include more explicit information about false positive results.
    • What is the optimal testing strategy for oropharyngeal Neisseria gonorrhoeae in men who have sex with men? Comparing selective testing versus routine universal testing from Dutch STI clinic data (2008-2017).

      van Liere, Geneviève A F S; Dukers-Muijrers, Nicole H T M; Wessel, Sophie Kuizenga; Götz, Hannelore M; Hoebe, Christian J P A (2019-09-26)
    • What Is the Optimal Time to Retest Patients With a Urogenital Chlamydia Infection? A Randomized Controlled Trial.

      van der Helm, Jannie J; Koekenbier, Rik H; van Rooijen, Martijn S; Schim van der Loeff, Maarten F; de Vries, Henry J C (2018-02)
      Chlamydia trachomatis is a common, often recurring sexually transmitted infection, with serious adverse outcomes in women. Current guidelines recommend retesting after a chlamydia infection, but the optimum timing is unknown. We assessed the optimal retest interval after urogenital chlamydia treatment.
    • When are Adverse Outcome Pathways and Associated Assays "Fit for Purpose" for Regulatory Decision-Making and Management of Chemicals?

      Coady, Katie; Browne, Patience; Embry, Michelle; Hill, Thomas; Leinala, Eeva; Steeger, Thomas; Maślankiewicz, Lidka; Hutchinson, Tom (2019-03-25)
      There have been increasing demands for chemical hazard and risk assessments in recent years. Chemical companies have expanded internal product stewardship initiatives, and jurisdictions have increased the regulatory requirements for the manufacture and sale of chemicals. There has also been a shift in chemical toxicity evaluations within the same timeframe with new methodologies being developed to improve chemical safety assessments for both human health and the environment. With increased needs for chemical assessments coupled with more diverse data streams from new technologies, regulators and others tasked with chemical management activities are faced with increasing workloads and more diverse types of data to consider. The Adverse Outcome Pathway (AOP) framework can be applied in different scenarios to integrate data and guide chemical assessment and management activities. In this paper, scenarios of how AOPs can be used to guide chemical management decisions during research and development, chemical registration, and subsequent regulatory activities like prioritization and risk assessment are considered. Furthermore, specific criteria (e.g. the type and level of AOP complexity, confidence in the AOP, as well as external review and assay validation) are proposed to examine whether AOPs and associated tools are fit for purpose when applied in different contexts. Certain toxicity pathways are recommended as priority areas for AOP research and development, and the continued use of AOPs and defined approaches in regulatory activities are recommended. Furthermore, a call for increased outreach, education and enhanced use of AOP databases are proposed to increase their utility in chemicals management. This article is protected by copyright. All rights reserved.
    • Which cancer survivors are at risk for a physically inactive and sedentary lifestyle? Results from pooled accelerometer data of 1447 cancer survivors.

      Sweegers, M G; Boyle, T; Vallance, J K; Chinapaw, M J; Brug, J; Aaronson, N K; D'Silva, A; Kampshoff, C S; Lynch, B M; Nollet, F; et al. (2019-08-16)
    • Who drops out and when? Predictors of non-response and loss to follow-up in a longitudinal cohort study among STI clinic visitors.

      van Wees, Daphne A; den Daas, Chantal; Kretzschmar, Mirjam E E; Heijne, Janneke C M (2019-01-01)
    • WHO Environmental Noise Guidelines for the European Region: A Systematic Review of Transport Noise Interventions and Their Impacts on Health.

      Brown, Alan Lex; van Kamp, Irene (2017-08-03)
      This paper describes a systematic review (1980-2014) of evidence on effects of transport noise interventions on human health. The sources are road traffic, railways, and air traffic. Health outcomes include sleep disturbance, annoyance, cognitive impairment of children and cardiovascular diseases. A conceptual framework to classify noise interventions and health effects was developed. Evidence was thinly spread across source types, outcomes, and intervention types. Further, diverse intervention study designs, methods of analyses, exposure levels, and changes in exposure do not allow a meta-analysis of the association between changes in noise level and health outcomes, and risk of bias in most studies was high. However, 43 individual transport noise intervention studies were examined (33 road traffic; 7 air traffic; 3 rail) as to whether the intervention was associated with a change in health outcome. Results showed that many of the interventions were associated with changes in health outcomes irrespective of the source type, the outcome or intervention type (source, path or infrastructure). For road traffic sources and the annoyance outcome, the expected effect-size can be estimated from an appropriate exposure-response function, though the change in annoyance in most studies was larger than could be expected based on noise level change.
    • WHO Environmental Noise Guidelines for the European Region: A Systematic Review on Environmental Noise and Cardiovascular and Metabolic Effects: A Summary.

      Kempen, Elise van; Casas, Maribel; Pershagen, Göran; Foraster, Maria (2018-02-22)
      To update the current state of evidence and assess its quality, we conducted a systematic review on the effects of environmental noise exposure on the cardio-metabolic systems as input for the new WHO environmental noise guidelines for the European Region. We identified 600 references relating to studies on effects of noise from road, rail and air traffic, and wind turbines on the cardio-metabolic system, published between January 2000 and August 2015. Only 61 studies, investigating different end points, included information enabling estimation of exposure response relationships. These studies were used for meta-analyses, and assessments of the quality of evidence using the Grading of Recommendations Assessment, Development and Evaluation (GRADE). A majority of the studies concerned traffic noise and hypertension, but most were cross-sectional and suffering from a high risk of bias. The most comprehensive evidence was available for road traffic noise and Ischeamic Heart Diseases (IHD). Combining the results of 7 longitudinal studies revealed a Relative Risk (RR) of 1.08 (95% CI: 1.01-1.15) per 10 dB (LDEN) for the association between road traffic noise and the incidence of IHD. We rated the quality of this evidence as high. Only a few studies reported on the association between transportation noise and stroke, diabetes, and/or obesity. The quality of evidence for these associations was rated from moderate to very low, depending on transportation noise source and outcome. For a comprehensive assessment of the impact of noise exposure on the cardiovascular and metabolic system, we need more and better quality evidence, primarily based on longitudinal studies.
    • WHO informal consultation on scientific basis for regulatory evaluation of candidate human vaccines from plants, Geneva, Switzerland, 24-25 January 2005.

      Laan, Jan Willem van der; Minor, Philip; Mahoney, Richard; Arntzen, Charles; Shin, Jinho; Wood, David (2006-05-15)
      In January 2005, WHO convened a meeting of leading experts in plant-derived vaccines and experts from regulatory authorities for an informal discussion on the state-of-the-art and to analyse whether specific guidance might be needed for plant-derived vaccines that is not yet provided by regulatory authorities. After a series of individual presentations, a general discussion was held to obtain a consensus on the need for further guidance. Both the presentations and the conclusions are presented. The meeting concluded that existing guidelines for the development, evaluation, and use of vaccines made by traditional methods can be applied to plant-derived vaccines. For plant-derived vaccines some specific issues will have to be addressed. These include, but are not restricted to, containment of the plants including disposal of waste materials. It was noted that plant-derived vaccines have been produced and clinically tested under US investigational new drug application, and all applicable regulatory and good manufacturing practice requirements are in place for this type of product. An innovator wishing to bring a plant-derived vaccine to market should consult closely with regulatory authorities to ensure that all appropriate studies are undertaken.
    • Whole genome sequence of Mycobacterium kansasii isolates of the genotype 1 from Brazilian patients with pulmonary disease demonstrates considerable heterogeneity.

      Machado, Edson; Vasconcellos, Sidra Ezidio Gonçalves; Cerdeira, Camillo; Gomes, Lia Lima; Junqueira, Ricardo; Carvalho, Luciana Distasio de; Ramos, Jesus Pais; Redner, Paulo; Campos, Carlos Eduardo Dias; Caldas, Paulo Cesar de Souza; et al. (2018-06-25)
      Mycobacterium kansasii is an opportunistic pathogen and one of the most commonly encountered species in individuals with lung disease. We here report the complete genome sequence of 12 clinical isolates of M. kansasii from patients with pulmonary disease in Brazil.
    • Whole genome sequencing of Mycobacterium tuberculosis: current standards and open issues.

      Meehan, Conor J; Goig, Galo A; Kohl, Thomas A; Verboven, Lennert; Dippenaar, Anzaan; Ezewudo, Matthew; Farhat, Maha R; Guthrie, Jennifer L; Laukens, Kris; Miotto, Paolo; et al. (2019-09-01)
    • Whole-Cell or Acellular Pertussis Primary Immunizations in Infancy Determines Adolescent Cellular Immune Profiles

      van der Lee, Saskia; Hendrikx, Lotte H.; Sanders, Elisabeth A. M.; Berbers, Guy A. M.; Buisman, Anne-Marie (2018-01-24)
    • Whole-cell or acellular pertussis vaccination in infancy determines IgG subclass profiles to DTaP booster vaccination.

      van der Lee, Saskia; Sanders, Elisabeth A M; Berbers, Guy A M; Buisman, Anne-Marie (2018)
      Duration of protection against pertussis is shorter in adolescents who have been immunized with acellular pertussis (aP) in infancy compared with adolescents who received whole-cell pertussis (wP) vaccines in infancy, which is related to immune responses elicited by these priming vaccines. To better understand differences in vaccine induced immunity, we determined pertussis, diphtheria, and tetanus (DTaP) vaccine antigen-specific IgG subclass responses in wP- and aP-primed children before and after two successive DTaP booster vaccinations.
    • Whole-Genome Characterization and Strain Comparison of VT2f-Producing Escherichia coli Causing Hemolytic Uremic Syndrome.

      Grande, Laura; Michelacci, Valeria; Bondì, Roslen; Gigliucci, Federica; Franz, Eelco; Badouei, Mahdi Askari; Schlager, Sabine; Minelli, Fabio; Tozzoli, Rosangela; Caprioli, Alfredo; et al. (2016)
      Verotoxigenic Escherichia coli infections in humans cause disease ranging from uncomplicated intestinal illnesses to bloody diarrhea and systemic sequelae, such as hemolytic uremic syndrome (HUS). Previous research indicated that pigeons may be a reservoir for a population of verotoxigenic E. coli producing the VT2f variant. We used whole-genome sequencing to characterize a set of VT2f-producing E. coli strains from human patients with diarrhea or HUS and from healthy pigeons. We describe a phage conveying the vtx2f genes and provide evidence that the strains causing milder diarrheal disease may be transmitted to humans from pigeons. The strains causing HUS could derive from VT2f phage acquisition by E. coli strains with a virulence genes asset resembling that of typical HUS-associated verotoxigenic E. coli.