The development of a culturally sensitive educational video: How to facilitate informed decisions on cervical cancer screening among Turkish- and Moroccan-Dutch women.

BACKGROUND: In the Netherlands, all women aged 30-60 years are invited to participate in the national cervical cancer screening programme, which is aimed at early detection and treatment of precancerous lesions. One fourth of the Dutch population has a migration background, with Turkish and Moroccan immigrants being the largest immigrant populations. Turkish- and Moroccan-Dutch women show lower screening participation rates and a higher incidence of cervical cancer, compared to native Dutch women. Since current information materials are not tailored to these women's needs, we developed a short culturally sensitive educational video to facilitate informed decision-making for cervical cancer screening among Turkish- and Moroccan-Dutch women. This article describes the development process of this video and the lessons learned. METHODS: Using the Entertainment-Education communication strategy, we collaborated with an interdisciplinary team of Turkish- and Moroccan-Dutch women, researchers, public health experts, and creative media professionals. We developed the video following the different stages of the Media Mapping model: Orientation, Crystallization, Design/Production, Implementation, and Dissemination. Each stage is described in the paper. RESULTS: The video was developed in Moroccan-Arabic, -Berber and Turkish, and emphasized three main themes: (1) more certainty about having cervical (pre)cancer and the possibility to prevent treatment, surgery, or premature death, and because of this, being there for the children, (2) according to the Islam, a woman should take good care of her health, and (3) anxiety, shame, and privacy. CONCLUSIONS: A short culturally sensitive educational video, delivered as part of a larger intervention together with the current information brochure, was developed based on theory and grounded in the needs of Turkish- and Moroccan-Dutch women. The value and effectiveness of this intervention to facilitate informed cervical cancer screening decisions are evaluated in a randomised controlled trial. PATIENT OR PUBLIC CONTRIBUTION: We collaborated with Turkish- and Moroccan-Dutch women during the development process of a short culturally sensitive educational video. Turkish- and Moroccan-Dutch women were also invited to watch the raw footage to verify whether the content and presentation matched their needs and requirements.

Hospital-based care and/or death followed by repatriation in Dutch travelers: The HAZARD study.

BACKGROUND: Travelers can experience health problems while abroad. This descriptive study aimed to quantify the disease burden leading to hospital-based care, repatriation or death in Dutch travelers during a stay in a foreign country, including Europe. METHODS: Retrospective study of demographic and clinical data from three medical assistance centers (MACs) and the Dutch Ministry of Foreign Affairs on Dutch travelers receiving hospital-based care or who died abroad in the years 2010-2014. Diagnoses were coded according to the International Classification of Diseases (ICD) and classified using the Global Burden of Disease tool. RESULTS: Data was available for 77,741 travelers' incidents: 75,385 medical consultations and 2,356 deaths. Four in five travelers received inpatient care, of which 36% concerned older travelers (65+) who had significantly longer hospital stays. Overall the top three diagnoses were: injuries (29%), infectious diseases (17%), and cardiovascular diseases (17%). Mental illness was reported in nearly 1.5% of the travelers. Incidence proportions were highest in South-Eastern Asia, with enteric infections as most common diagnosis. Injuries and communicable diseases occurred most often in South-Eastern Asia, while non-communicable diseases were mostly reported in South America. One in five travelers who consulted a physician was repatriated back home, mostly on a scheduled flight with or without medical escort. Cardiovascular diseases and injuries were the leading causes of death. CONCLUSIONS: Not only communicable diseases, but also injuries and chronic diseases (in particular cardiovascular diseases) frequently affected travelers' health while staying abroad and frequently necessitated hospital-based care. This should be addressed during the pre-travel counseling.

Decision-making, barriers, and facilitators regarding cervical cancer screening participation among Turkish and Moroccan women in the Netherlands: a focus group study.

OBJECTIVES: Whether the lower Dutch cervical cancer (CC) screening participation of Turkish- and Moroccan-Dutch women is based on informed decision-making is unknown. Our aim was to explore how and why Turkish- and Moroccan-Dutch women decide to participate or not in the current Dutch CC screening programme as well as to learn their perceptions on self-sampling.DESIGN: Six focus group discussions were conducted between March and April 2019 with Turkish (n = 24) and Moroccan (n = 20) women in the Netherlands, aged 30-60 years. Questions were based on an extended version of the Health Belief Model. Discussions were transcribed verbatim and thematically analysed.RESULTS: Participants lacked knowledge about CC and its screening, and seemed to be unaware of the cons of CC screening. Perceived barriers for screening were lack of a good command of the Dutch language, having a male general practitioner, fatalism, shame and taboo, and associations of CC with lack of femininity and infertility. Other barriers were fear of the test result, cancer, suffering, death, and leaving their children behind after death. Perceived facilitators were a high perceived severity of disease, social support, and short procedure time. An additional religious facilitator included the responsibility to take care of one's own health using medical options that God provided. Participants had low self-efficacy expectations towards performing correct self-sampling.CONCLUSIONS: Although participants' informed-decision making seems to be limited, this study showed that women do not only consider factual medical information, but also practical, emotional, cultural, and religious aspects prior to deciding to screen or not. Information materials should be tailored to these aspects, as well as translated to appropriate languages due to lack of a good command of the Dutch language. Self-efficacy expectations towards performing correct self-sampling should be enhanced to promote informed CC screening participation among Turkish- and Moroccan-Dutch women.

Applications and Recruitment Performance of Web-Based Respondent-Driven Sampling: Scoping Review.

BACKGROUND: Web-based respondent-driven sampling is a novel sampling method for the recruitment of participants for generating population estimates, studying social network characteristics, and delivering health interventions. However, the application, barriers and facilitators, and recruitment performance of web-based respondent-driven sampling have not yet been systematically investigated. OBJECTIVE: Our objectives were to provide an overview of published research using web-based respondent-driven sampling and to investigate factors related to the recruitment performance of web-based respondent-driven sampling. METHODS: We conducted a scoping review on web-based respondent-driven sampling studies published between 2000 and 2019. We used the process evaluation of complex interventions framework to gain insights into how web-based respondent-driven sampling was implemented, what mechanisms of impact drove recruitment, what the role of context was in the study, and how these components together influenced the recruitment performance of web-based respondent-driven sampling. RESULTS: We included 18 studies from 8 countries (high- and low-middle income countries), in which web-based respondent-driven sampling was used for making population estimates (n=12), studying social network characteristics (n=3), and delivering health-related interventions (n=3). Studies used web-based respondent-driven sampling to recruit between 19 and 3448 participants from a variety of target populations. Studies differed greatly in the number of seeds recruited, the proportion of successfully recruiting participants, the number of recruitment waves, the type of incentives offered to participants, and the duration of data collection. Studies that recruited relatively more seeds, through online platforms, and with less rigorous selection procedures reported relatively low percentages of successfully recruiting seeds. Studies that did not offer at least one guaranteed material incentive reported relatively fewer waves and lower percentages of successfully recruiting participants. The time of data collection was shortest in studies with university students. CONCLUSIONS: Web-based respondent-driven sampling can be successfully applied to recruit individuals for making population estimates, studying social network characteristics, and delivering health interventions. In general, seed and peer recruitment may be enhanced by rigorously selecting and motivating seeds, offering at least one guaranteed material incentive, and facilitating adequate recruitment options regarding the target population's online connectedness and communication behavior. Potential trade-offs should be taken into account when implementing web-based respondent-driven sampling, such as having less opportunities to implement rigorous seed selection procedures when recruiting many seeds, as well as issues around online rather than physical participation, such as the risk of cheaters participating repeatedly.

Clustering of chronic hepatitis B screening intentions in social networks of Moroccan immigrants in the Netherlands.

BACKGROUND: Early detection, identification, and treatment of chronic hepatitis B through screening is vital for those at increased risk, e.g. born in hepatitis B endemic countries. In the Netherlands, Moroccan immigrants show low participation rates in health-related screening programmes. Since social networks influence health behaviour, we investigated whether similar screening intentions for chronic hepatitis B cluster within social networks of Moroccan immigrants. METHODS: We used respondent-driven sampling (RDS) where each participant ("recruiter") was asked to complete a questionnaire and to recruit three Moroccans ("recruitees") from their social network. Logistic regression analyses were used to analyse whether the recruiters' intention to request a screening test was similar to the intention of their recruitees. RESULTS: We sampled 354 recruiter-recruitee pairs: for 154 pairs both participants had a positive screening intention, for 68 pairs both had a negative screening intention, and the remaining 132 pairs had a discordant intention to request a screening test. A tie between a recruiter and recruitee was associated with having the same screening intention, after correction for sociodemographic variables (OR 1.70 [1.15-2.51]). CONCLUSIONS: The findings of our pilot study show clustering of screening intention among individuals in the same network. This provides opportunities for social network interventions to encourage participation in hepatitis B screening initiatives.

Serological response to three alternative series of hepatitis B revaccination (Fendrix, Twinrix, and HBVaxPro-40) in healthy non-responders: a multicentre, open-label, randomised, controlled, superiority trial.

BACKGROUND: Serological non-response can be present after hepatitis B vaccination in healthy adults. We aimed to establish which of three revaccination regimens is most effective at inducing protective immunity METHODS: Healthy adults (aged 18-80 years) from 16 Dutch centres (13 public health services, two university hospitals, and one travel clinic) were included in this multicentre, parallel group, randomised, controlled, superiority trial. The inclusion criterion was vaccine non-response (hepatitis B surface antibody [anti-HBs] titre <10 IU/L) after a primary series with three doses of one type of recombinant vaccine against hepatitis B virus (either HBVaxPro-10 or Engerix-B at months 0, 1, and 6). Participants were individually randomly assigned (1:1:1:1) to a vaccination series of repeated initial vaccination (HBVaxPro 10 µg or Engerix-B 20 µg) as the control, or to Twinrix 20 µg, Fendrix 20 µg, or HBVaxPro 40 µg. We used a web-based randomisation programme, stratified by centre, with a block size of four. Participants and centres were unmasked to assignment after randomisation. Laboratory staff and investigators were masked to vaccine-group assignment. All revaccination schedules were identical, with intramuscular vaccinations at 0, 1, and 2 months. Anti-HBs was measured at 0, 1, 2, and 3 months. The primary outcome was the percentage of responders (anti-HBs titres ≥10 IU/L) at 3 months. Immunogenicity and safety analyses were based on an intention-to-vaccinate analysis, the immunogenicity analysis with last observation carried forward for missing data, and the Bonferroni and the Benjamini-Hochberg method were applied to correct for multiple testing. The trial was registered in the Dutch National Trial Register and inclusion has been stopped (identifier NL3011; EudraCT-number 2011-005627-40). FINDINGS: The participants were recruited between Nov 1, 2012, and Sept 1, 2017. 480 participants were randomly assigned and included in intention-to-vaccinate analyses: 124 (26%) to control, 118 (25%) to Twinrix, 114 (24%) to HBVaxPro-40, and 124 (26%) to Fendrix. At month 3 the percentage of responders was 83 (67%) of 124 (95% CI 57·9-75·1 in the control group, 94 (80%) of the 118 (71·3-86·5) in the Twinrix group, 95 (83%) of 114 (75·2-89·7) in the HBVaxPro-40 group, and 108 (87%) of 124 (79·9-92·4) in the Fendrix group. Compared with the control group, the percentage of responders was superior for the HBVaxPro-40 group (adjusted difference 21·6% [95% CI 10·4-32·7], p=0·0204 [Bonferroni corrected p value]) and the Fendrix group (26·3% [15·4-37·3], p=0·0006), but not the Twinrix group (25·0% [13·0-37·0]; p=0·0846). One serious adverse event occurred (herpes zoster ophthalmicus) in the Fendrix group, which was not attributed to the vaccine. INTERPRETATION: Revaccinating healthy non-responders with Fendrix or HBVaxPro-40 resulted in significantly higher proportions of responders and therefore indication for these vaccines should be expanded to enable revaccination of non-responders. FUNDING: National Institute for Public Health and the Environment.

Timeliness of infectious disease reporting, the Netherlands, 2003 to 2017: law change reduced reporting delay, disease identification delay is next.

BackgroundTimely notification of infectious diseases is essential for effective disease control and needs regular evaluation.AimOur objective was to evaluate the effects that statutory adjustments in the Netherlands in 2008 and raising awareness during outbreaks had on notification timeliness.MethodsIn a retrospective analyses of routine surveillance data obtained between July 2003 and November 2017, delays between disease onset and laboratory confirmation (disease identification delay), between laboratory confirmation and notification to Municipal Health Services (notification delay) and between notification and reporting to the National Institute for Public Health and the Environment (reporting delay) were analysed for 28 notifiable diseases. Delays before (period 1) and after the law change (periods 2 and 3) were compared with legal timeframes. We studied the effect of outbreak awareness in 10 outbreaks and the effect of specific guidance messages on disease identification delay for two diseases.ResultsWe included 144,066 notifications. Average notification delay decreased from 1.4 to 0.4 days across the three periods (six diseases; p < 0.05), reporting delay decreased mainly in period 2 (from 0.5 to 0.1 days, six diseases; p < 0.05). In 2016-2017, legal timeframes were met overall. Awareness resulted in decreased disease identification delay for three diseases: measles and rubella (outbreaks) and psittacosis (specific guidance messages).ConclusionsLegal adjustments decreased notification and reporting delays, increased awareness reduced identification delays. As disease identification delay dominates the notification chain, insight in patient, doctor and laboratory delay is necessary to further improve timeliness and monitor the impact of control measures during outbreaks.

A stochastic simulation model to study respondent-driven recruitment.

Respondent-driven detection is a chain recruitment method used to sample contact persons of infected persons in order to enhance case finding. It starts with initial individuals, so-called seeds, who are invited for participation. Afterwards, seeds receive a fixed number of coupons to invite individuals with whom they had contact during a specific time period. Recruitees are then asked to do the same, resulting in successive waves of contact persons who are connected in one recruitment tree. However, often the majority of participants fail to invite others, or invitees do not accept an invitation, and recruitment stops after several waves. A mathematical model can help to analyse how various factors influence peer recruitment and to understand under which circumstances sustainable recruitment is possible. We implemented a stochastic simulation model, where parameters were suggested by empirical data from an online survey, to determine the thresholds for obtaining large recruitment trees and the number of waves needed to reach a steady state in the sample composition for individual characteristics. We also examined the relationship between mean and variance of the number of invitations sent out by participants and the probability of obtaining a large recruitment tree. Our main finding is that a situation where participants send out any number of coupons between one and the maximum number is more effective in reaching large recruitment trees, compared to a situation where the majority of participants does not send out any invitations and a smaller group sends out the maximum number of invitations. The presented model is a helpful tool that can assist public health professionals in preparing research and contact tracing using online respondent-driven detection. In particular, it can provide information on the required minimum number of successfully sent invitations to reach large recruitment trees, a certain sample composition or certain number of waves.

Hepatitis B in Moroccan-Dutch: a quantitative study into determinants of screening participation.

BACKGROUND: In November 2016, the Dutch Health Council recommended hepatitis B (HBV) screening for first-generation immigrants from HBV endemic countries. However, these communities show relatively low attendance rates for screening programmes, and our knowledge on their participation behaviour is limited. We identified determinants associated with the intention to request an HBV screening test in first-generation Moroccan-Dutch immigrants. We also investigated the influence of non-refundable costs for HBV screening on their intention. METHODS: Offline and online questionnaires were distributed among first- and second/third-generation Moroccan-Dutch immigrants using respondent-driven sampling. Random forest analyses were conducted to determine which determinants had the greatest impact on (1) the intention to request an HBV screening test on one's own initiative, and (2) the intention to participate in non-refundable HBV screening at €70,-. RESULTS: Of the 379 Moroccan-Dutch respondents, 49.3% intended to request a test on their own initiative, and 44.1% were willing to attend non-refundable screening for €70,-. Clarity regarding infection status, not having symptoms, fatalism, perceived self-efficacy, and perceived risk of having HBV were the strongest predictors to request a test. Shame and stigma, fatalism, perceived burden of screening participation, and social influence of Islamic religious leaders had the greatest predictive value for not intending to participate in screening at €70,- non-refundable costs. Perceived severity and possible health benefit were facilitators for this intention measure. These predictions were satisfyingly accurate, as the random forest method retrieved area under the curve scores of 0.72 for intention to request a test and 0.67 for intention to participate in screening at €70,- non-refundable costs. CONCLUSIONS: By the use of respondent-driven sampling, we succeeded in studying screening behaviour among a hard-to-reach minority population. Despite the limitations associated with correlated data and the sampling method, we recommend to (1) incorporate clarity regarding HBV status, (2) stress the risk of an asymptomatic infection, (3) emphasise mother-to-child transmission as the main transmission route, and (4) team up with Islamic religious leaders to help decrease elements of fatalism, shame, and stigma to enhance screening uptake of Moroccan immigrants in the Netherlands.

Hepatitis B in Moroccan-Dutch: a qualitative study into determinants of screening participation.

Background: Chronic hepatitis B (HBV) leads to an increased risk for liver cirrhosis and liver cancer. In the Netherlands, chronic HBV prevalence in the general population is 0.20%, but 3.77% in first generation immigrants. Our aim was to identify determinants associated with the intention to participate in HBV testing among first generation Moroccan immigrants, one of the two largest immigrant groups targeted for screening. Methods: Semi-structured interviews were held with first (n = 9) and second generation (n = 10) Moroccan-Dutch immigrants, since second generation immigrants frequently act as their parents' brokers in healthcare. Results: Most participants had little knowledge about hepatitis B, but had a positive attitude towards screening. Facilitators for screening intention were perceived susceptibility to and severity of disease, positive attitude regarding prevention, wishing to know their hepatitis B status and to prevent potential hepatitis B transmission to others. Additional cultural facilitators included fear (of developing cancer), and existing high health care utilization; a religious facilitator was the responsibility for one's own health and that of others. Barriers included lack of awareness and knowledge, practical issues, not having symptoms, negative attitude regarding prevention, fear about the test result and low-risk perception. A cultural barrier was shame and stigma, and a religious barrier was fatalism. Conclusion: We identified important facilitators and barriers, which we found, can be interpreted differently. Specific and accurate information should be provided, accompanied by strategies to address shame and stigma, in which Islamic religious leaders could play a role in bringing information across.

Which recommendations are considered essential for outbreak preparedness by first responders?

BACKGROUND: Preparedness is considered essential for healthcare organizations to respond effectively to outbreaks. In the current study we aim to capture the views of first responders on what they consider key recommendations for high quality preparedness. Furthermore, we identified the recommendations with the highest urgency from the perspective of first responders. METHODS: We chose a multistep approach using a systematic Delphi procedure. Previously extracted recommendations from scientific literature were presented to a national and two international expert panels. We asked the experts to score the recommendations based on relevance for high quality preparedness. In addition we asked them to choose the ten most urgent recommendations. RESULTS: Starting with 80 recommendations from scientific literature, 49 key recommendations were selected by both international expert panels. Differences between both panels were mainly on triage protocols. In addition, large differences were found in the selection of the ten most urgent recommendations. CONCLUSIONS: In this study infectious disease experts selected a set of key recommendations representing high quality preparedness and specified which ones should be given the highest urgency when preparing for a future crisis. These key recommendations can be used to shape their preparedness activities.

ICARES: a real-time automated detection tool for clusters of infectious diseases in the Netherlands.

BACKGROUND: Clusters of infectious diseases are frequently detected late. Real-time, detailed information about an evolving cluster and possible associated conditions is essential for local policy makers, travelers planning to visit the area, and the local population. This is currently illustrated in the Zika virus outbreak. METHODS: In the Netherlands, ICARES (Integrated Crisis Alert and Response System) has been developed and tested on three syndromes as an automated, real-time tool for early detection of clusters of infectious diseases. From local general practices, General Practice Out-of-Hours services and a hospital, the numbers of routinely used syndrome codes for three piloted tracts i.e., respiratory tract infection, hepatitis and encephalitis/meningitis, are sent on a daily basis to a central unit of infectious disease control. Historic data combined with information about patients' syndromes, age cohort, gender and postal code area have been used to detect clusters of cases. RESULTS: During the first 2 years, two out of eight alerts appeared to be a real cluster. The first was part of the seasonal increase in Enterovirus encephalitis and the second was a remarkably long lasting influenza season with high peak incidence. CONCLUSIONS: This tool is believed to be the first flexible automated, real-time cluster detection system for infectious diseases, based on physician information from both general practitioners and hospitals. ICARES is able to detect and follow small regional clusters in real time and can handle any diseases entity that is regularly registered by first line physicians. Its value will be improved when more health care institutions agree to link up with ICARES thus improving further the signal-to-noise ratio.

Atypical aetiology in patients hospitalised with community-acquired pneumonia is associated with age, gender and season; a data-analysis on four Dutch cohorts.

BACKGROUND: Microorganisms causing community-acquired pneumonia (CAP) can be categorised into viral, typical and atypical (Legionella species, Coxiella burnetii, Mycoplasma pneumoniae, and Chlamydia species). Extensive microbiological testing to identify the causative microorganism is not standardly recommended, and empiric treatment does not always cover atypical pathogens. In order to optimize epidemiologic knowledge of CAP and to improve empiric antibiotic choice, we investigated whether atypical microorganisms are associated with a particular season or with the patient characteristics age, gender, or chronic obstructive pulmonary disease (COPD). METHODS: A data-analysis was performed on databases from four prospective studies, which all included adult patients hospitalised with CAP in the Netherlands (N = 980). All studies performed extensive microbiological testing. RESULTS: A main causative agent was identified in 565/980 (57.7 %) patients. Of these, 117 (20.7 %) were atypical microorganisms. This percentage was 40.4 % (57/141) during the non-respiratory season (week 20 to week 39, early May to early October), and 67.2 % (41/61) for patients under the age of 60 during this season. Factors that were associated with atypical causative agents were: CAP acquired in the non-respiratory season (odds ratio (OR) 4.3, 95 % CI 2.68-6.84), age <60 year (OR 2.9, 95 % CI 1.83-4.66), male gender (OR 1.7, 95 % CI 1.06-2.71) and absence of COPD (OR 0.2, 95 % CI 0.12-0.52). CONCLUSIONS: Atypical causative agents in CAP are associated with respectively non-respiratory season, age <60 years, male gender and absence of COPD. Therefore, to maximise its yield, extensive microbiological testing should be considered in patients <60 years old who are admitted with CAP from early May to early October. TRIAL REGISTRATION: NCT00471640 , NCT00170196 (numbers of original studies).

Fluctuation of Viremia in Hepatitis B Virus-Infected Healthcare Workers Performing Exposure-Prone Procedures in the Netherlands.

OBJECTIVE: To determine the longitudinal changes in viral load of hepatitis B virus (HBV)-infected healthcare workers (HCWs) and its consequences for exclusion of infected HCWs performing exposure-prone procedures, various HBV DNA safety thresholds, and the frequency of monitoring. DESIGN: Retrospective cohort study June 1, 1996-January 31, 2013. Participants In the Netherlands, chronically HBV-infected HCWs performing exposure-prone procedures are notified to the Committee for Prevention of Iatrogenic Hepatitis B. Of the 126 notified HCWs, 45 had 2 or more HBV DNA levels determined without antiviral therapy. METHODS: A time-to-event analysis for HBV-infected HCWs categorized in various viremia levels surpassing a HBV DNA threshold level of 1×105 copies/mL, above which exposure-prone procedures are not allowed in the Netherlands. RESULTS: Fluctuations of HBV DNA in follow-up samples ranged from -5.4 to +2.2 log10 copies/mL. A high correlation was seen for each HBV DNA level with the 3 previous levels. In a time-to-event analysis, after 6 months 7.2%, 6.5%, and 14.3% of individuals had surpassed the threshold of 1×105 copies/mL for viral load categories 4.8×103 to 1.5×104; 1.5×104 to 4.0×104; and 4.0×104 to 1.0×105, respectively. CONCLUSIONS: We propose standard retesting every 6 months, with more frequent retesting just below the high threshold value (1×105 copies/mL), and prolonging this standard interval to 1 year after 3 consecutive levels below the threshold in policies with lower safety thresholds (1×103 or 1×104 copies/mL). Infect Control Hosp Epidemiol 2016;37:655-660.

Tracking social contact networks with online respondent-driven detection: who recruits whom?

BACKGROUND: Transmission of respiratory pathogens in a population depends on the contact network patterns of individuals. To accurately understand and explain epidemic behaviour information on contact networks is required, but only limited empirical data is available. Online respondent-driven detection can provide relevant epidemiological data on numbers of contact persons and dynamics of contacts between pairs of individuals. We aimed to analyse contact networks with respect to sociodemographic and geographical characteristics, vaccine-induced immunity and self-reported symptoms. METHODS: In 2014, volunteers from two large participatory surveillance panels in the Netherlands and Belgium were invited for a survey. Participants were asked to record numbers of contacts at different locations and self-reported influenza-like-illness symptoms, and to invite 4 individuals they had met face to face in the preceding 2 weeks. We calculated correlations between linked individuals to investigate mixing patterns. RESULTS: In total 1560 individuals completed the survey who reported in total 30591 contact persons; 488 recruiter-recruit pairs were analysed. Recruitment was assortative by age, education, household size, influenza vaccination status and sentiments, indicating that participants tended to recruit contact persons similar to themselves. We also found assortative recruitment by symptoms, reaffirming our objective of sampling contact persons whom a participant may infect or by whom a participant may get infected in case of an outbreak. Recruitment was random by sex and numbers of contact persons. Relationships between pairs were influenced by the spatial distribution of peer recruitment. CONCLUSIONS: Although complex mechanisms influence online peer recruitment, the observed statistical relationships reflected the observed contact network patterns in the general population relevant for the transmission of respiratory pathogens. This provides useful and innovative input for predictive epidemic models relying on network information.

Estimation of acute and chronic Q fever incidence in children during a three-year outbreak in the Netherlands and a comparison with international literature.

BACKGROUND: In the Dutch 2007-2009 Q fever outbreak Coxiella burnetii was transmitted aerogenically from dairy goat farms to those living in the surrounding areas. Relatively few children were reported. The true number of pediatric infections is unknown. In this study, we estimate the expected number of acute and chronic childhood infections. METHODS: As Coxiella was transmitted aerogenic to those living near infected dairy goat farms, we could use adult seroprevalence data to estimate infection risk for inhabitants, children and adults alike. Using Statistics Netherlands data we estimated the number of children at (high) risk for developing chronic Q fever. Literature was reviewed for childhood (0-15 years) Q fever reports and disease rates. We compared this with Dutch reported and our estimated data for 2007-2009. RESULTS: In The Netherlands epidemic, 44 children were reported (1.2 % of total notifications). The childhood incidence was 0.15 compared to 2.6 per 10,000 inhabitants for adults. No complications were reported. Based on the expected similarity in childhood and adult exposure we assume that 9.8 % of children in the high-risk area had Q fever infection, resulting in 1562 acute infections during the Q fever epidemic interval. Based on the prevalence of congenital heart disease, at least 13 children are at high risk for developing chronic Q fever. In medical literature, 42 case reports described 140 childhood Q fever cases with a serious outcome (four deaths). In chronic Q fever, cardiac infections were predominant. Four outbreaks were reported involving children, describing 11 childhood cases. 36 National and/or regional studies reported seroprevalences varying between 0 and 70 %. CONCLUSION: In the 3-year Dutch epidemic, few childhood cases were reported, with pulmonary symptoms leading, and none with a serious presentation. With an estimated 13 high-risk children for chronic infection in the high exposure area, and probably forty in the whole country, we may expect several chronic Q fever complications in the coming years in paediatric practice.

Enhancing Syndromic Surveillance With Online Respondent-Driven Detection.

OBJECTIVES: We investigated the feasibility of combining an online chain recruitment method (respondent-driven detection) and participatory surveillance panels to collect previously undetected information on infectious diseases via social networks of participants. METHODS: In 2014, volunteers from 2 large panels in the Netherlands were invited to complete a survey focusing on symptoms of upper respiratory tract infections and to invite 4 individuals they had met in the preceding 2 weeks to take part in the study. We compared sociodemographic characteristics among panel participants, individuals who volunteered for our survey, and individuals recruited via respondent-driven detection. RESULTS: Starting from 1015 panel members, the survey spread through all provinces of the Netherlands and all age groups in 83 days. A total of 433 individuals completed the survey via peer recruitment. Participants who reported symptoms were 6.1% (95% confidence interval = 5.4, 6.9) more likely to invite contact persons than were participants who did not report symptoms. Participants with symptoms invited more symptomatic recruits to take part than did participants without symptoms. CONCLUSIONS: Our findings suggest that online respondent-driven detection can enhance identification of symptomatic patients by making use of individuals' local social networks.

Context analysis for epidemic control in the Netherlands.

When epidemics occur, experts advise the Ministries on effective control measures. There is uncertainty in the translation of epidemiological evidence into effective outbreak management interventions, due to contradicatory problem perspectives, diverse interests and time pressure. Several models have been developed that aim to integrate societal context information in risk assessment to improve the feasibility and the implementation of adviced measures. The current study explored the views of relevant public officials on this issue using the Rapid Risk Assessment of Acute Public Health Events model of the World Health Organization. Eighteen public officials involved in infectious disease risk assessment and policy making in the Netherlands participated in semi-structured qualitative interviews. Their experiences, expectations and expert opinions on the use of societal context information for infectious disease outbreak control were explored. Most interviewees consider information on societal context necessary for infectious disease risk management. However, different perspectives exist on which information is relevant, and how, when, why and by whom it should be obtained. We conclude that outbreak control could benefit from systematically gathered information on the societal context. This requires identifying which information is beneficial and selecting or designing methods to obtain it. Explicit stakeholder assessment seems a first step.

Developing requirements for a mobile app to support citizens in dealing with ticks and tick bites via end-user profiling.

Tick bites and tick-borne infections are an increasingly large problem. There is a wide range of precautions that citizens can take, but compliance is low. Mobile technology can offer a solution here, as they allow citizens to access health information in context. In this article, we discuss the development of requirements for a mobile app to support citizens in dealing with ticks and tick bites. First, we identified organizational stakeholders based on relevant protocols, and primary end-users via a systematic risk determination procedure. Then, we profiled end-users based on 25 in-depth interviews. We consulted organizational stakeholders via a focus group. The mobile app should primarily motivate citizens to check themselves for tick bites after visiting a risk area. The app should also include a tick radar, alerts to remind people to check for tick bites, and the possibility to document tick bites. Our experiences underline the necessity of thoroughly investigating the designated end-users and their context of use in order to tailor preventive health advice, and we demonstrate how this can be done. Finally, this case shows the need to create persuasive health technology in order to maximize citizen compliance.

Comparison of contact patterns relevant for transmission of respiratory pathogens in Thailand and The Netherlands using respondent-driven sampling.

Understanding infection dynamics of respiratory diseases requires the identification and quantification of behavioural, social and environmental factors that permit the transmission of these infections between humans. Little empirical information is available about contact patterns within real-world social networks, let alone on differences in these contact networks between populations that differ considerably on a socio-cultural level. Here we compared contact network data that were collected in The Netherlands and Thailand using a similar online respondent-driven method. By asking participants to recruit contact persons we studied network links relevant for the transmission of respiratory infections. We studied correlations between recruiter and recruited contacts to investigate mixing patterns in the observed social network components. In both countries, mixing patterns were assortative by demographic variables and random by total numbers of contacts. However, in Thailand participants reported overall more contacts which resulted in higher effective contact rates. Our findings provide new insights on numbers of contacts and mixing patterns in two different populations. These data could be used to improve parameterisation of mathematical models used to design control strategies. Although the spread of infections through populations depends on more factors, found similarities suggest that spread may be similar in The Netherlands and Thailand.