Contribution of sexual health services to hepatitis B detection and control (Netherlands, 2008-2016).

OBJECTIVES: Case finding is one of the priority actions to reduce the disease burden of chronic hepatitis B (CHB). We estimated the contribution of CHB case finding at sexual health centres (SHCs) to the total national number of newly diagnosed CHB cases in the Netherlands and determined the characteristics of CHB cases detected at SHCs. METHODS: This observational study used surveillance data from all outpatient SHCs in the Netherlands (SOAP database) and the number of CHB from national notification data (Osiris) from 2008 to 2016. The proportion of CHB notifications (hepatitis B surface antigen positive serology) detected at SHCs was calculated. SHC consultations without hepatitis B virus (HBV) testing (n=669 308), with acute hepatitis B diagnosis (n=73), with HBV vaccination only (n=182) or an inconclusive hepatitis B diagnosis (n=24) were excluded. Univariable and multivariable logistic regression analyses were performed, stratified by gender and sexual preference, to analyse patient characteristics associated with CHB. RESULTS: During the study period, 12 149 CHB cases were notified. 405 646 SHC consultations were included in the analysis and 1452 CHB cases (0.4%) were detected at SHCs. The proportion of CHB cases detected at SHCs in relation to the national notified number ranged between 12.4% (200 of 1613) in 2008 and 10.8% (106 of 980) in 2016. 87% of CHB cases were among first-generation migrants (FGMs) originating from high endemic countries for sexually transmitted infections or men who have sex with men (MSM). In multivariable analysis, an older age category, migration background and being a commercial sex worker (CSW) were associated with CHB in all stratified analyses. CONCLUSIONS: The contribution of SHCs is relevant to case finding of CHB in the Netherlands. SHCs should therefore be considered as an important health setting to screen for HBV in high-risk groups, especially among MSM, CSW and FGM, to achieve a reduction in the HBV-related disease burden.

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.

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.

Evaluation of a Web-Based Culturally Sensitive Educational Video to Facilitate Informed Cervical Cancer Screening Decisions Among Turkish- and Moroccan-Dutch Women Aged 30 to 60 Years: Randomized Intervention Study.

BACKGROUND: In the Netherlands, since 1996, a national cervical cancer (CC) screening program has been implemented for women aged 30 to 60 years. Regional screening organizations send an invitation letter and information brochure in Dutch to the home addresses of targeted women every 5 years. Although this screening is free of charge, Turkish- and Moroccan-Dutch women, especially, show low screening participation and limited informed decision-making (IDM). As Turkish- and Moroccan-Dutch women indicated their need for information on the practical, emotional, cultural, and religious aspects of CC screening, we developed a culturally sensitive educational video (CSEV) as an addition to the current information brochure. OBJECTIVE: In this study, we aimed to evaluate the added effect of the CSEV on IDM regarding CC screening participation among Turkish and Moroccan women aged 30 to 60 years in the Netherlands through a randomized intervention study. METHODS: Initial respondents were recruited via several social media platforms and invited to complete a web-based questionnaire. Following respondent-driven sampling, respondents were asked to recruit a number of peers from their social networks to complete the same questionnaire. Respondents were randomly assigned to the control (current information brochure) or intervention condition (brochure and CSEV). We measured respondents' knowledge and attitude regarding CC screening and their intention to participate in the next CC screening round before and after the control or intervention condition. We evaluated the added effect of the CSEV (above the brochure) on their knowledge, attitude, intention, and IDM using intention-to-treat analyses. RESULTS: The final sample (n=1564) included 686 (43.86%) Turkish and 878 (56.14%) Moroccan-Dutch women. Of this sample, 50.7% (793/1564) were randomized to the control group (350/793, 44.1% Turkish and 443/793, 55.9% Moroccan) and 49.3% (771/1564) to the intervention group (336/771, 43.6% Turkish and 435/771, 56.4% Moroccan). Among the Turkish-Dutch women, 33.1% (116/350) of the control respondents and 40.5% (136/336) of the intervention respondents consulted the brochure (not statistically significant). Among Moroccan-Dutch women, these percentages were 28.2% (125/443) and 37.9% (165/435), respectively (P=.003). Of all intervention respondents, 96.1% (323/336; Turkish) and 84.4% (367/435; Moroccan) consulted the CSEV. The CSEV resulted in more positive screening attitudes among Moroccan-Dutch women than the brochure (323/435, 74.3% vs 303/443, 68.4%; P=.07). Women, who had never participated in CC screening before, showed significantly more often a positive attitude toward CC screening compared with the control group (P=.01). CONCLUSIONS: Our short and easily implementable CSEV resulted in more positive screening attitudes, especially in Moroccan-Dutch women. As the CSEV was also watched far more often than the current brochure was read, this intervention can contribute to better reach and more informed CC screening decisions among Turkish- and Moroccan-Dutch women. TRIAL REGISTRATION: International Clinical Trial Registry Platform NL8453; https://tinyurl.com/2dvbjxvc.

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.

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.

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).

Quantifying reporting timeliness to improve outbreak control.

The extent to which reporting delays should be reduced to gain substantial improvement in outbreak control is unclear. We developed a model to quantitatively assess reporting timeliness. Using reporting speed data for 6 infectious diseases in the notification system in the Netherlands, we calculated the proportion of infections produced by index and secondary cases until the index case is reported. We assumed interventions that immediately stop transmission. Reporting delays render useful only those interventions that stop transmission from index and secondary cases. We found that current reporting delays are adequate for hepatitis A and B control. However, reporting delays should be reduced by a few days to improve measles and mumps control, by at least 10 days to improve shigellosis control, and by at least 5 weeks to substantially improve pertussis control. Our method provides quantitative insight into the required reporting delay reductions needed to achieve outbreak control and other transmission prevention goals.

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.

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.

Underdiagnosis of foodborne hepatitis A, The Netherlands, 2008-2010(1.).

Outbreaks of foodborne hepatitis A are rarely recognized as such. Detection of these infections is challenging because of the infection's long incubation period and patients' recall bias. Nevertheless, the complex food market might lead to reemergence of hepatitis A virus outside of disease-endemic areas. To assess the role of food as a source of infection, we combined routine surveillance with real-time strain sequencing in the Netherlands during 2008-2010. Virus RNA from serum of 248 (59%) of 421 reported case-patients could be sequenced. Without typing, foodborne transmission was suspected for only 4% of reported case-patients. With typing, foodborne transmission increased to being the most probable source of infection for 16%. We recommend routine implementation of an enhanced surveillance system that includes prompt forwarding and typing of hepatitis A virus RNA isolated from serum, standard use of questionnaires, data sharing, and centralized interpretation of data.

Public knowledge and preventive behavior during a large-scale Salmonella outbreak: results from an online survey in the Netherlands.

BACKGROUND: Food-borne Salmonella infections are a worldwide concern. During a large-scale outbreak, it is important that the public follows preventive advice. To increase compliance, insight in how the public gathers its knowledge and which factors determine whether or not an individual complies with preventive advice is crucial. METHODS: In 2012, contaminated salmon caused a large Salmonella Thompson outbreak in the Netherlands. During the outbreak, we conducted an online survey (n = 1,057) to assess the general public's perceptions, knowledge, preventive behavior and sources of information. RESULTS: Respondents perceived Salmonella infections and the 2012 outbreak as severe (m = 4.21; five-point scale with 5 as severe). Their knowledge regarding common food sources, the incubation period and regular treatment of Salmonella (gastro-enteritis) was relatively low (e.g., only 28.7% knew that Salmonella is not normally treated with antibiotics). Preventive behavior differed widely, and the majority (64.7%) did not check for contaminated salmon at home. Most information about the outbreak was gathered through traditional media and news and newspaper websites. This was mostly determined by time spent on the medium. Social media played a marginal role. Wikipedia seemed a potentially important source of information. CONCLUSIONS: To persuade the public to take preventive actions, public health organizations should deliver their message primarily through mass media. Wikipedia seems a promising instrument for educating the public about food-borne Salmonella.

Hepatitis B vaccination of men who have sex with men in the Netherlands: should we vaccinate more men, younger men or high-risk men?

OBJECTIVES: The selective vaccination programme against hepatitis B virus (HBV) was introduced in the Netherlands in 2002 targeting high-risk groups, including men who have sex with men (MSM). Despite the high average age of vaccination in MSM, the number of notifications of acute HBV recently declined. We investigate whether this can be attributed to the selective vaccination programme. We examine how vaccination strategies could be improved and the impact of universal infant vaccination introduced in 2011. METHODS: We use a mathematical model for HBV transmission among MSM. The incidence of HBV was calculated from the model and from notification data of acute HBV. RESULTS: A decline was observed in the incidence of HBV since 2006, as calculated from the model; this decline was smaller than that observed in data if all MSM were equally likely to be vaccinated. Assuming that high-risk MSM were more likely to be vaccinated than low-risk MSM resulted in a steeper decline in modelled incidence and better agreement with observed incidence. Vaccinating MSM at a younger age or doubling the vaccination rate would increase the impact of selective vaccination, but is less effective than vaccinating high-risk MSM. CONCLUSIONS: Selective HBV vaccination of MSM in the Netherlands has had a substantial impact in reducing HBV incidence. The reduction suggests that vaccination rates among high-risk MSM were higher than those among low-risk MSM. Countries that have not yet reached 35-year cohorts with universal childhood vaccination should actively implement or continue selective high-risk MSM vaccination.

Modeling the transmission risk of emerging infectious diseases through blood transfusion.

BACKGROUND: A timely risk assessment is desired to guide decisions on preventive transfusion safety measures during emerging infectious disease (EID) outbreaks. The European Up-Front Risk Assessment Tool (EUFRAT) model was developed to provide quantitative transmission risk estimates of EIDs through blood transfusion. STUDY DESIGN AND METHODS: The generic model comprises five sequential steps to estimate the infection risks in the blood transfusion chain: 1) the prevalence of infection in the donor population, 2) the risk of obtaining infected donations, 3) infected components, 4) infected blood products, and 5) the risk of transmitting the infection to recipients. The model uses inputs from epidemiologic characteristics of an EID and transfusion practice. The model was applied to data from a recent chikungunya outbreak in Italy. RESULTS: Based on data from the outbreak peak, an estimated prevalence of 1.07 (95% confidence interval [CI], 0.38-2.03) per 100,000 donors would lead to 0.04 infected donations (95% CI, 0.01-0.10), 0.13 infected blood components, 0.13 infected end products, and 0.0001 severe infections in recipients. This estimated risk can be reduced by increasing the duration of quarantine of the donated blood and becomes zero after 7 or more days of quarantine. The model also estimated the probability of a donor returning from the outbreak area and subsequently donating infected blood in his home country to be 0.30 (95% CI, 0.01-0.65) per 100,000. CONCLUSION: The model can be used to quantify EID outbreak risks to blood transfusion recipients and the effect of targeted safety interventions and as such support public health decision-making.

Study on public perceptions and protective behaviors regarding Lyme disease among the general public in the Netherlands: implications for prevention programs.

BACKGROUND: Lyme disease (LD) is the most common tick-borne disease in the United States and in Europe. The aim of this study was to examine knowledge, perceived risk, feelings of anxiety, and behavioral responses of the general public in relation to tick bites and LD in the Netherlands. METHODS: From a representative Internet panel a random sample was drawn of 550 panel members aged 18 years and older (8-15 November 2010) who were invited to complete an online questionnaire. RESULTS: Response rate (362/550, 66%). This study demonstrates that knowledge, level of concern, and perceived efficacy are the main determinants of preventive behavior. 35% (n = 125/362) of the respondents reported a good general knowledge of LD. While 95% (n = 344/362) perceived LD as severe or very severe, the minority (n = 130/362, 36%) perceived their risk of LD to be low. Respondents were more likely to check their skin after being outdoors and remove ticks if necessary, than to wear protective clothing and/or use insect repellent skin products. The percentage of respondents taking preventive measures ranged from 6% for using insect repellent skin products, to 37% for wearing protective clothing. History of tick bites, higher levels of knowledge and moderate/high levels of worry were significant predictors of checking the skin. Significant predictors of wearing protective clothing were being unemployed/retired, higher knowledge levels, higher levels of worry about LD and higher levels of perceived efficacy of wearing protective clothing. CONCLUSIONS: Prevention programs targeting tick bites and LD should aim at influencing people's perceptions and increasing their knowledge and perceived efficacy of protective behavior. This can be done by strengthening motivators (e.g. knowledge, concern about LD, perceived efficacy of wearing protective clothing) and removing barriers (e.g. low perceived personal risk, not knowing how to recognize a tick). The challenge is to take our study findings and translate them into appropriate prevention strategies.