Chronic hepatitis B and C infections in the Netherlands: estimated prevalence in risk groups and the general population.

Chronic hepatitis B virus (HBV) and hepatitis C virus (HCV) infections are usually asymptomatic for decades, thus targeted screening can prevent liver disease by timely diagnosis and linkage to care. More robust estimates of chronic HBV and HCV infections in the general population and risk groups are needed. Using a modified workbook method, the total number of ever chronically infected individuals in the Netherlands in 2016 was determined using population size and prevalence estimates from studies in the general and high-risk population. The estimated 2016 chronic HBV infection prevalence is 0.34% (low 0.22%, high 0.47%), corresponding to approximately 49 000 (low 31 000, high 66 000) HBV-infected individuals aged 15 years and older. The estimated ever-chronic HCV infection prevalence is 0.16% (low 0.06%, high 0.27%), corresponding to approximately 23 000 (low 8000, high 38 000) ever-chronic HCV-infected individuals. The prevalence of chronic HBV and HCV infections in the Netherlands is low. First-generation migrants account for most infections with 81% and 60% of chronic HBV and HCV infections, respectively. However, about one-fifth of HCV infections is found in the general population at low risk. This method can serve as an example for countries in need of more accurate prevalence estimates, to help the design and evaluation of prevention and control policies.

Under-vaccinated groups in Europe and their beliefs, attitudes and reasons for non-vaccination; two systematic reviews.

BACKGROUND: Despite effective national immunisation programmes in Europe, some groups remain incompletely or un-vaccinated ('under-vaccinated'), with underserved minorities and certain religious/ideological groups repeatedly being involved in outbreaks of vaccine preventable diseases (VPD). Gaining insight into factors regarding acceptance of vaccination of 'under-vaccinated groups' (UVGs) might give opportunities to communicate with them in a trusty and reliable manner that respects their belief system and that, maybe, increase vaccination uptake. We aimed to identify and describe UVGs in Europe and to describe beliefs, attitudes and reasons for non-vaccination in the identified UVGs. METHODS: We defined a UVG as a group of persons who share the same beliefs and/or live in socially close-knit communities in Europe and who have/had historically low vaccination coverage and/or experienced outbreaks of VPDs since 1950. We searched MEDLINE, EMBASE and PsycINFO databases using specific search term combinations. For the first systematic review, studies that described a group in Europe with an outbreak or low vaccination coverage for a VPD were selected and for the second systematic review, studies that described possible factors that are associated with non-vaccination in these groups were selected. RESULTS: We selected 48 articles out of 606 and 13 articles out of 406 from the first and second search, respectively. Five UVGs were identified in the literature: Orthodox Protestant communities, Anthroposophists, Roma, Irish Travellers, and Orthodox Jewish communities. The main reported factors regarding vaccination were perceived non-severity of traditional "childhood" diseases, fear of vaccine side-effects, and need for more information about for example risk of vaccination. CONCLUSIONS: Within each UVG identified, there are a variety of health beliefs and objections to vaccination. In addition, similar factors are shared by several of these groups. Communication strategies regarding these similar factors such as educating people about the risks associated with being vaccinated versus not being vaccinated, addressing their concerns, and countering vaccination myths present among members of a specific UVG through a trusted source, can establish a reliable relationship with these groups and increase their vaccination uptake. Furthermore, other interventions such as improving access to health care could certainly increase vaccination uptake in Roma and Irish travellers.

Preparedness and the importance of meeting the needs of healthcare workers: a qualitative study on Ebola.

BACKGROUND: Healthcare workers (HCWs) face specific challenges in infectious disease outbreaks, which provide unusual, new events with exposure risk. The fear of infection or new, unknown tasks in an unfamiliar setting, for example, may complicate outbreak management. AIM: To gain insight into how healthcare organizations can prepare to meet the needs of their HCWs by capturing the experiences of HCWs with patients with suspected Ebola virus disease. METHODS: We conducted 23 in-depth interviews with HCWs, of whom 20 worked in a Dutch university hospital and three worked in a regional ambulance service. We invited HCWs who cared for patients with suspected Ebola or who were on the team preparing for admission of such patients in the period 2014-2015. FINDINGS: The HCWs were stressed and anxious, but most rated their overall experience as positive. We categorized the reported experiences in three main themes, namely, experiences related to: (i) the novelty of the threat, (ii) the risk of infection and fear of transmission, and (iii) the excessive attention. Our results underline the importance of a supportive working environment suitable for crises. CONCLUSION: The experiences of HCWs dealing with patients with suspected Ebola can direct improvements in generic preparedness for highly transmissible diseases.

Prevention of tick bites: an evaluation of a smartphone app.

BACKGROUND: Lyme borreliosis (LB) is the most common reported tick-borne infection in Europe, and involves transmission of Borrelia by ticks. As long as a vaccine is not available and effective measures for controlling tick populations are insufficient, LB control is focused on preventive measures to avoid tick bites. To inform citizens about the risk of ticks, motivate them to check for tick bites, and encourage them to remove any attached tick as quickly as possible, a mobile app called 'Tekenbeet' (Dutch for 'tick bite') was developed and released. The aim of this study was to evaluate the usage and user satisfaction of the 'Tekenbeet' app and to investigate whether it affects users' knowledge, perceived severity, perceived susceptibility, self-efficacy, response efficacy, current behavior and intention to comply with preventive measures. METHODS: Usage of the app was evaluated with data obtained from Google Analytics. A survey among the Dutch general adult population with two data collection periods evaluated the usage, user satisfaction and its influence on abovementioned outcomes. RESULTS: Data obtained from Google Analytics showed the app was downloaded almost 40,000 in the 20 months following the launch. The 'tick radar' and 'tick diary' screens were viewed most often. In addition, a total of 554 respondents completed an online survey. The mean user satisfaction score was 7.44 (on a scale of 1-10) and 90.9% of respondents would recommend the app to others. On average, survey respondents who downloaded the app (n = 243) recorded significantly more often higher knowledge scores (OR 3.37; 95% CI 2.02-5.09) and had a higher intention to comply with preventive measures (OR 2.47; 95% CI 1.22-5.85) compared to respondents who did not download the app (n = 311). CONCLUSIONS: The 'Tekenbeet' app is a frequently used and well-appreciated educational tool to increase public knowledge of ticks and tick bites. It also helps to improve the user's intention to apply preventive measures. The use of smartphones and apps is now commonplace in the Netherlands; the 'Tekenbeet' app feeds into this trend and thereby offers a modern day alternative to established formats such as an information leaflet and information provision on the Internet.

Targeted outreach hepatitis B vaccination program in high-risk adults: The fundamental challenge of the last mile.

BACKGROUND: The aim of this study was to evaluate the cost-effectiveness of the on-going decentralised targeted hepatitis B vaccination program for behavioural high-risk groups operated by regional public health services in the Netherlands since 1-November-2002. Target groups for free vaccination are men having sex with men (MSM), commercial sex workers (CSW) and hard drug users (HDU). Heterosexuals with a high partner change rate (HRP) were included until 1-November-2007. METHODS: Based on participant, vaccination and serology data collected up to 31-December-2012, the number of participants and program costs were estimated. Observed anti-HBc prevalence was used to estimate the probability of susceptible individuals per risk-group to become infected with hepatitis B virus (HBV) in their remaining life. We distinguished two time-periods: 2002-2006 and 2007-2012, representing different recruitment strategies and target groups. Correcting for observed vaccination compliance, the number of future HBV-infections avoided was estimated per risk-group. By combining these numbers with estimates of life-years lost, quality-of-life losses and healthcare costs of HBV-infections - as obtained from a Markov model-, the benefit of the program was estimated for each risk-group separately. RESULTS: The overall incremental cost-effectiveness ratio of the program was €30,400/QALY gained, with effects and costs discounted at 1.5% and 4%, respectively. The program was more cost-effective in the first period (€24,200/QALY) than in the second period (€42,400/QALY). In particular, the cost-effectiveness for MSM decreased from €20,700/QALY to €47,700/QALY. DISCUSSION AND CONCLUSION: This decentralised targeted HBV-vaccination program is a cost-effective intervention in certain unvaccinated high-risk adults. Saturation within the risk-groups, participation of individuals with less risky behaviour, and increased recruitment investments in the second period made the program less cost-effective over time. The project should therefore discus how to reduce costs per risk-group, increase effects or when to integrate the vaccination in regular healthcare.

Using typing techniques in a specific outbreak: the ethical reflection of public health professionals.

Typing techniques are laboratory methods used in outbreak management to investigate the degree to which microbes found within an outbreak are related. Knowledge about relational patterns between microbes benefits outbreak management, but inevitably also tells us something about the relational patterns of the people hosting them. Since the technique is often used without explicit consent of all individuals involved, this may raise ethical questions. The aim of this study was to unravel the complex ethical deliberation of professionals over the use of such techniques. We organised group discussions (n = 3) with Dutch outbreak managers (n = 23). The topic list was based on previously identified ethical issues and discussions were analysed for recurrent themes. We found that outbreak managers first and foremost reflect on the balance of individual harm with public health benefit. This key question was approached by way of discussing four more specific ethical themes: (1) justification of governmental intervention, (2) responsibility to prevent infections, (3) scientific uncertainty and (4) legal consequences. The themes found in this study, rephrased into accessible questions, represent the shared ethical understanding of professionals and can help to articulate the ethical dimensions of using molecular science in response to infectious disease outbreaks.

Signs of stigma and poor mental health among carriers of MRSA.

BACKGROUND: Many countries have implemented guidelines to prevent transmission of meticillin-resistant Staphylococcus aureus (MRSA). Important contextual factors of stigma can be identified in the context of MRSA. Over the past decade, concerns have been raised over a possible stigmatizing effect of these actions. AIM: To identify and quantify the occurrence of MRSA-associated stigma, and to explore its association with mental health in a country with an MRSA 'search and destroy' policy. METHODS: In 2014, a questionnaire study among 57 Dutch MRSA carriers (people that carry MRSA without signs of MRSA infection) was performed. Stigma was measured with an adjusted version of the Berger HIV Stigma Scale. Mental health was measured with the five-item RAND Mental Health Inquiry. FINDINGS: Thirty-two (56%) MRSA carriers reported stigma; of these, eight (14%) reported 'clear stigma' (Berger score >110) and 24 (42%) reported 'suggestive for stigma' (Berger score 76-110). Educational level, female sex and intensive MRSA eradication therapy were associated with higher stigma scores. Poor mental health (RAND score <60) was reported by 33% of MRSA carriers. Stigma and mental health scores were inversely correlated. Stigma was experienced most frequently in healthcare settings, and was seldom experienced in the religious community or at sport facilities. CONCLUSION: A substantial proportion of MRSA carriers reported stigma due to MRSA, and stigma was associated with poor mental health. Anticipation of MRSA-associated stigma is warranted, both in the way that care is delivered by hospital staff and in the way that care is organized within the hospital.

Ethnic and regional differences in STI clinic use: a Dutch epidemiological study using aggregated STI clinic data combined with population numbers.

OBJECTIVES: Ethnic minorities (EM) from STI-endemic countries are at increased risk to acquire an STI. The objectives of this study were to investigate the difference in STI clinic consultation and positivity rates between ethnic groups, and compare findings between Dutch cities. METHODS: Aggregated population numbers from 2011 to 2013 of 15-44 year-old citizens of Amsterdam, Rotterdam, The Hague and Utrecht extracted from the population register (N=3 129 941 person-years) were combined with aggregated STI clinic consultation data in these cities from the national STI surveillance database (N=113 536). Using negative binomial regression analyses (adjusted for age and gender), we compared STI consultation and positivity rates between ethnic groups and cities. RESULTS: Compared with ethnic Dutch (consultation rate: 40.3/1000 person-years), EM from Eastern Europe, Sub-Sahara Africa, Suriname, the Netherlands Antilles/Aruba and Latin America had higher consultation rates (range relative risk (RR): 1.27-2.26), whereas EM from Turkey, North Africa, Asia and Western countries had lower consultation rates (range RR: 0.29-0.82). Of the consultations among ethnic Dutch, 12.2% was STI positive. Positivity rates were higher among all EM groups (range RR: 1.14-1.81). Consultation rates were highest in Amsterdam and lowest in Utrecht independent of ethnic background (range RR Amsterdam vs Utrecht: 4.30-10.30). Positivity rates differed less between cities. CONCLUSIONS: There were substantial differences in STI clinic use between ethnic groups and cities in the Netherlands. Although higher positivity rates among EM suggest that these high-risk individuals reach STI clinics, it remains unknown whether their reach is optimal. Special attention should be given to EM with comparatively low consultation rates.

Outbreak of severe sepsis due to contaminated propofol: lessons to learn.

Nosocomial infections are a frequent concern in healthcare. Despite the available knowledge on nosocomial infections and preventive measures, outbreaks of infections continue to occur. An outbreak of severe sepsis in patients who underwent minor procedures in an operating theatre during two consecutive days is described and analysed in this study. We performed a retrospective cohort study using epidemiological data in order to investigate the source of infection together with microbiological and on-site investigations and interviews. Seven patients met the case definition of postoperative systemic inflammatory response syndrome (SIRS). All other patients operated on over the same period served as controls. Of the risk factors investigated, general anaesthesia and propofol were statistically significant (P=0.003). Klebsiella pneumoniae and Serratia marcescens were cultured from opened vials of propofol, propofol-related devices and from blood cultures from two of the patients. These strains were genotypically indistinguishable. Lapses in aseptic preparation, handling and storage of the propofol were observed, and were the most probable cause of the extrinsic contamination. The daily procedure of handling propofol was not performed according to the manufacturer's recommendations, the main departure being the use of a single-use vial for multiple patients. This study documents the risk of infection due to contaminated propofol and the importance of having written guidelines for its handling.

Update: a food-borne outbreak of hepatitis A in the Netherlands related to semi-dried tomatoes in oil, January-February 2010.

Between 31 December 2009 and 10 February 2010, 13 patients were infected by an identical hepatitis A virus strain not previously detected in the Netherlands. They had not been abroad and were widely distributed over the Netherlands. A case-control study including 12 cases and 44 controls identified semi-dried tomatoes in oil as the source of the outbreak (odds ratio: 20.0; 95% confidence interval: 1.5-274). The virus was not detected in any of 81 tested food samples. International trace-back is still ongoing.

A possible foodborne outbreak of hepatitis A in the Netherlands, January-February 2010.

As of 1 March 2010, a total of 11 primary cases with onset of symptoms between 31 December 2009 and 10 February 2010, have been identified with identical hepatitis A genotype IB strains in the Netherlands. A relation with Australian and French foodborne outbreaks occurring in 2009 and 2010 is suspected. Ten of the 11 primary cases indicated that they had consumed one or more products containing semi-dried tomatoes during their incubation period.

Which factors are important in adults' uptake of a (pre)pandemic influenza vaccine?

Since 2008, (pre)pandemic vaccines against H5N1 influenza have been available and pandemic vaccines against new influenza H1N1 are currently produced. In The Netherlands, the vaccination call for seasonal influenza among the recommended groups approximates 70%. These statistics raise the question if adults in Western societies are willing to get a (pre)pandemic influenza vaccination, for example, against avian H5N1 or swine-like H1N1 virus. A questionnaire was performed to determine the predictors of a negative intention to be immunized against pandemic influenza among adults. Demographical, behavioural and organisational determinants were studied. Thirty-four and five percent of the respondents were negatively intended to get a pandemic influenza vaccination in a pre-pandemic or pandemic phase, respectively. On the basis of six behavioural determinants negative intention to get a pandemic influenza vaccination can be predicted correctly in almost 80% of the target group. These determinants should be targeted in pandemic preparedness plans.

Epidemiology and control of influenza A(H1N1)v in the Netherlands: the first 115 cases.

Introductions of the new influenza A(H1N1) variant virus in the Netherlands led to enhanced surveillance and infection control. By 24 June 2009, 115 cases were reported, of whom 44% were indigenously acquired. Severity of disease is similar to reports elsewhere. Our point estimate of the effective reproductive number (Re) for the initial phase of the influenza A(H1N1)v epidemic in the Netherlands was below one. Given that the Re estimate is based on a small number of indigenous cases and a limited time period, it needs to be interpreted cautiously.

Hepatitis B virus infected health care workers in The Netherlands, 2000-2008.

In response to the confirmed transmission of hepatitis B virus (HBV) from a surgeon to several patients in the Netherlands, a 'Committee for Prevention of Iatrogenic Hepatitis B' was established in 2000. During the years 2000-2008, the committee reviewed 99 cases of HBV-infected health care workers. Fifty of them were found to perform exposure prone procedures (EPPs). Because of high levels of HBV DNA (>100,000 copies/ml), a ban on performing EPPs was applied in 11/50 cases; 25/50 low-viremic health care workers were allowed to continue EPPs while their HBV load was being monitored; and 14/50 cases had stopped working or changed profession. In five restricted workers who started oral antiviral treatment, HBV replication was persistently suppressed, enabling the ban on EPPs to be lifted. Throughout the European Union different levels of HBV viremia have been chosen, above which health care workers are not allowed to perform EPPs. It remains unknown how this affects the safety of patients. Application in the Netherlands of a European or a British guideline would have, respectively, doubled or tripled the number of restricted health care workers.

A prolonged outbreak of Salmonella Typhimurium infection related to an uncommon vehicle: hard cheese made from raw milk.

In 2006, in The Netherlands, an outbreak of Salmonella Typhimurium phage type 561 (STM DT7, corresponding to the rare DT7 in the international typing scheme) was detected, accumulating to over 200 cases. By telephone interviews, data were collected from all laboratory-confirmed cases. In addition, in August 2006, a case-control study was performed in a subset of cases. Environmental and microbiological investigation was performed on a suspected dairy farm. In the case-control study (51 cases, 105 matched controls), hard cheese purchased from a farm, specifically farm X, and from a market stall were found to be associated with infection. The dairy production room of farm X tested STM DT7-positive in August. However, it was only in November, after earlier unsuccessful attempts, that a low-level contamination was confirmed in the hard farmhouse cheese, triggering control measures. A timely and adequate response was hampered during this outbreak for several reasons. Measures for improvement in handling future similar incidents are discussed.

Significance of isolated antibody to hepatitis B core antigen in Dutch national vaccination campaign of behavioural high-risk groups.

In the Dutch national vaccination campaign for behavioural risk groups, anti-HBcore is used as the primary HBV screening test. Samples with positive results undergo testing for active infection (HBsAg) but are otherwise accepted as indicating past infection, thereby assuming immunity. This study evaluated evidence for immunity in the target population screened on the basis of this algorithm, by re-analysing 1000 anti-HBcore-positive blood samples equally divided among risk groups: 14.7% of confirmed anti-HBcore lacked anti-HBs ('isolated' anti-HBcore). Independent risk factors for isolated anti-HBcore were risk group, HCV infection in hard-drug users (DU) and origin from Sub-Saharan Africa. After extrapolation, the proportion of participants who were said to be immune but lacked any additional evidence of immunity amounted to 9.6% (ranging from 12.5% in DU to 6.5% in men who have sex with men). It is recommended that as a minimum anti-HBs screening is included in testing algorithms used to determine vaccination programmes for risk groups, in particular in DU.

Changes in prevention and outbreak management of Legionnaires disease in the Netherlands between two large outbreaks in 1999 and 2006.

We describe an outbreak of Legionnaires' disease in 2006 in Amsterdam, the Netherlands. Comparisons with the outbreak that took place in 1999 are made to evaluate changes in legionella prevention and outbreak management. The 2006 outbreak was caused by a wet cooling tower. Thirty-one patients were reported. The outbreak was detected two days after the first patient was admitted to hospital, and the source was eliminated five days later. The 1999 outbreak was caused by a whirlpool at a flower show, and 188 patients were reported. This outbreak was detected 14 days after the first patient was admitted to hospital, and two days later the source was traced. Since 1999, the awareness of legionellosis among physicians, the availability of a urinary antigen tests and more efficient early warning and communication systems improved the efficiency of legionellosis outbreak management. For prevention, extensive legislation with clear responsibilities has been put in place. For wet cooling towers, however, legislation regarding responsibility and supervision of maintenance needs to be improved.

[Possible exposure to rabies in anamnesis: rabies advice in the Netherlands]. / Mogelijke blootstelling aan rabiës in de anamnese: rabiesadvisering in Nederland.

Anamnestic incidences of four patients have highlighted the potential risk ofexposure to rabies. The first patient was a 30-year-old woman who rescued a bat from the mouth of her dog; it bit her on the right wrist. In the Netherlands, bats may be infected with the Lyssa virus. The Preparedness and Response Unit (PRU) of the Centre for Infectious Disease Control (CIDC) advised human rabies immunoglobulin (HRIG) and a full vaccination programme. The second patient was a 37-year-old woman, who caught a 'sick' squirrel and was subsequently bitten on her left hand. The advice was not to use post exposure prophylaxis since rabies is not prevalent amongst squirrels in the Netherlands. The third patient, a 55-year-old man, was bitten on his right calf by a dog in Sri Lanka. He was treated with HRIG and given the full vaccination course. The fourth patient was a 14-month-old boy who was scratched on the face by a cat in Turkey. He immediately received the first vaccination and upon return to the Netherlands was treated with HRIG and the other vaccinations. All patients remained without symptoms. A structured approach for risk assessment of each potential rabies incident is possible. It requires balancing a number of criteria: the species of animal, the endemicity of rabies in a country, the observed health or vaccination status of an animal, whether the animal can be tested for rabies, if the exposure was provoked or unprovoked, the type of injury and its location on the body of the injured, and the time interval between administration of HRIG and vaccine. In the Netherlands all health care providers are expected to perform a proper risk assessment. They may seek advice from regional health departments (Municipal Health Services), who, in turn, can be assisted by the PRU. HRIG and vaccine are only provided by the National Vaccine Institute in Bilthoven.