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.

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.

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.

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.

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.

[An outbreak of Q fever in The Netherlands--possible link to goats]. / Een uitbraak van Q-koorts in Nederland--mogelijk verband met geiten.

In 2007, 73 cases of Q fever were identified through reports and retrospective analyses; the affected region extended from Tilburg in the southwest to Arnhem in the northeast. The infections arose in late spring, particularly in May and June. Several spontaneous abortions due to Q fever occurred on 4 dairy goat farms in the same region. The national incidence of spontaneous abortion due to Q fever was 6 cases in 2006 and 7 in 2007. Climatically, this southern region was extraordinarily dry during April 2007. All pregnant women from a small region with the highest incidence in northeast North Brabant were called for diagnostic testing. Infected patients were followed for symptoms and ultrasound was performed as indicated. A definitive source of the infection could not yet be identified. Favourable climatic conditions were suspected as the cause for the combination of widespread dissemination among goats and transmission to humans. Q fever is a zoonosis caused by Coxiella burnetti, a microorganism dispersed in great numbers in the area in which an infected animal gives birth. C. burnetti is particularly resistant to chemical and physical factors and can disperse by air across large distances under dry climatic conditions. Q fever should be considered in patients in The Netherlands who present with lower airway infection and, in rare cases, hepatitis. Reporting atypical clusters ofpneumonia to the Municipal Health Service (GGD) is advisable. The GGD maintains close contact with Animal Health Services, which is aware of current infectious animal diseases. Targeted investigation can identify the source of infection and eliminate it. Greater awareness can prevent delays in diagnosis and treatment and help identify chronic forms at an early stage or prevent them.

[The use of antiviral agents during an (impending) influenza pandemic]. / Het gebruik van antivirale middelen tijdens een (dreigende) influenzapandemie.

The preventive and therapeutic principles during an (impending) influenza pandemic differ fundamentally from those prevailing during the annual episodes ofinfluenza. Pending the availability of an effective pandemic vaccine, neuraminidase inhibitors are the only effective agents for the prevention and treatment of infections caused by a pandemic influenza virus. The development of an influenza pandemic has 6 phases: phases 3-5 reflect an increasing threat; phase 6 represents a manifest pandemic. During phases 3-5, a maximum effort is made to prevent or delay a pandemic. Neuraminidase inhibitors should be given not only to patients but also to their close contacts (post-exposure prophylaxis). During phase 6, post-exposure prophylaxis is no longer indicated and neuraminidase inhibitors are prescribed for all patients with symptoms ofpandemic influenza. Prophylaxis without preceding close contact with an influenza patient (primary prophylaxis) is recommended only in exceptional cases. Physicians should not prescribe antiviral drugs on demand to concerned citizens for stockpiling.

Public health implications of using various case definitions in The Netherlands during the worldwide SARS outbreak.

This study analysed the consequences of deviation from the WHO case definition for the assessment of patients with suspected severe acute respiratory syndrome (SARS) in The Netherlands during 2003. Between 17 March and 7 July 2003, as a result of dilemmas in balancing sensitivity and specificity, five different case definitions were used. The patients referred for SARS assessment were analysed from a public health perspective. None of the patients referred had SARS, based on serological and virological criteria. Nevertheless, all 72 patients required thorough assessment and, depending on the results of the assessment, institution of appropriate prevention and control measures. Changing case definitions caused confusion in classifying cases. A centralised assessment of the reported cases by a team with clinical and public health expertise (epidemiological and geographical risk assessment) is a practical solution for addressing differences in applying case definitions. The burden of managing non-cases is an important issue when allocating public health resources, and should be taken into account during the preparation phase, rather than during an outbreak. This applies not only to SARS, but also to other public health threats, such as pandemic influenza or a bioterrorist episode.

[Avian influenza H5NI in Europe: little risk as yet to health in the Netherlands]. / Vogelgriep H5NI in Europa: vooralsnog gering gezondheidsrisico voor Nederland.

Since 2004, outbreaks of fowl plague caused by a highly pathogenic avian influenza virus of the subtype A/H5NI have been reported from various countries in Southeast Asia. To date, 118 cases with 61 deaths have been documented in humans, due to close contact with infected poultry or raw poultry meat. Although efficient human-to-human transmission has not occurred, in a few cases transmission to blood relatives could not be ruled out. In October 2005, outbreaks of A/H5NI in poultry and wild fowl have been confirmed from Turkey, Romania and Russia, due probably to infection via migratory birds. The direct risk of infection in humans in Europe is very low and is associated with direct exposure to infected poultry. In order to address the long-term risk of a pandemic due to recombination of human and avian viruses or to mutations in the avian virus itself, guidelines for pandemic preparedness have been developed and implemented in the Netherlands.

[Rubella epidemic in the Netherlands, 2004/'05: awareness of congenital rubella syndrome required]. / Rubella-epidemie in Nederland in 2004/'05: alertheid op congenitaal rubellasyndroom vereist.

Rubella is a public health problem due to the teratogenic effects associated with primary rubella infection during pregnancy (congenital rubella syndrome). Following universal rubella vaccination of infants in the Netherlands, the incidence of rubella has declined dramatically. However, since September 2004, an outbreak has occurred among unvaccinated individuals, most of whom declined vaccination based on religious beliefs. In the period 1 September 2004-22 March 2005, 166 cases of rubella were reported, including 12 pregnant women. Monitoring for signs that the epidemic has spread to other populations in the Netherlands is important because this might indicate the need for additional interventions. Awareness among health-care workers of the possible occurrence of congenital rubella syndrome should be raised. The clinical manifestations of congenital rubella syndrome are diverse, can be transient or permanent, and may not present until adolescence or adulthood. All cases of laboratory-confirmed rubella infection and congenital rubella syndrome should be reported to municipal health authorities. There is a possibility that this outbreak will spread abroad. The WHO aims to reduce the incidence of congenital rubella syndrome to < 1/100,000 live births. Health-care workers in the Netherlands should be extra alert to detect and notify rubella in a timely manner.

[Pneumococcal vaccination; arguments for informing parents about the options available]. / Pneumokokkenvaccinatie; argumenten om ouders te informeren over de mogelijkheden.

Invasive pneumococcal disease in childhood causes meningitis, sepsis and pneumonia. Current pneumococcal vaccines are estimated to prevent 50% of Dutch pneumococcal meningitis and 40% of pneumococcal sepsis. In 2001, the Health Council of The Netherlands emphasised the importance of universal pneumococcal vaccination of small children. However, the Dutch Minister of Health, Welfare and Sports stated that the vaccine is too expensive for the national vaccination programme (NVP). Child health clinics do not educate parents about vaccines that are not available in the NVP, and therefore parents are not informed about the availability of an effective pneumococcal vaccine. We argue that child health clinic physicians should inform parents about the limitations of the NVP in order to put expectations about the programme into perspective. Educating parents that the NVP is very worthwhile but does not include every possible or available vaccine will strengthen confidence in the NVP. Parents who then want to know which effective vaccines are available should be provided with the information they request. In view of the Health Council recommendations, the pneumococcal vaccine should then be specifically mentioned.

[The control of infectious diseases in The Netherlands]. / Infectieziektebestrijding in Nederland.

Municipal health services (MHSs) carry out the control and prevention of communicable diseases, under the authority of the municipal councils. Mayors have the authority to enforce measures aimed at individuals, such as isolation and quarantine. The mandatory notification of infectious diseases by physicians, as required by the Infectious Diseases Act, is an essential part of infectious disease control. By collecting these notifications, MHSs obtain a much better picture than the individual physician of the mutual relationships between the reported cases. MHSs monitor current regional developments, while the National Institute for Public Health and the Environment (RIVM) does this for the entire country and elsewhere in the world. By means of electronic message service, the information can be disseminated immediately, if necessary, to health professionals everywhere in The Netherlands. In case of national threats or epidemics, the National Coordination of Infectious Disease Control (LCI) can request expert advice from the Outbreak Management Team and can advise the Minister of Public Health, Welfare and Sport (VWS) as to the best control measures. The Minister is chairman of a board of administrators, defines the policy and bears the final responsibility. The Ministry of VWS creates the necessary conditions. The Minister of VWS has noted structural errors in the organisation of the prevention of infectious diseases and will implement an improved organisational structure in the beginning of 2005. The assignments of the new centre are not only research and advising, but also the overall management of the prevention.

['Severe acute respiratory syndrome' (SARS): epidemiology, clinical signs, diagnosis and prevention]. / 'Severe acute respiratory syndrome' (SARS): epidemiologie, kliniek, diagnostiek en preventie.

Severe acute respiratory syndrome (SARS) is caused by a recently identified Coronavirus (SARS-CoV). The clinical symptoms are non-specific and during the first few days in particular, are not clinically distinguishable from those of many other viral or bacterial infections. The majority of infected patients develop pneumonia within a week of the first symptoms appearing. Since November 2002 the virus has spread from South China to almost 30 other countries, where about 8500 infected individuals have been registered; about 800 people have already died from the disease (9.5%). The number of infected persons includes a noticeably high percentage of health workers. This fact underlines the importance of good infection prevention measures for each patient contact. The implementation of hygienic measures requires attention, because the infection of personnel in Toronto hospitals still occurred after the virus and transmission routes were known. It appears that transmission can be prevented with relatively simple precautions, as long as these are consistently implemented. Early recognition and isolation of a possible source are an essential part of this. SARS is a group A notifiable disease (report if suspected). In the Netherlands the general practitioner has a prominent role in assessing and treating individuals who are infected or might be infected with SARS-CoV. A protocol and a detailed action plan are available. In addition to this hospitals should be prepared for the initial reception of a patient with SARS, who presents directly to the outpatients' clinic or Casualty Department.

Why do gay men want to be vaccinated against hepatitis B? An assessment of psychosocial determinants of vaccination intention.

We assessed to what extent gay men are motivated to obtain vaccination against hepatitis B virus (HBV), as well as the social cognitive determinants of this motivation. A cross-sectional survey was conducted among homosexual men by means of a written questionnaire that contained assessments of intention, knowledge and social-cognitive determinants of intention (i.e. attitude, social norm and perceived behavioural control towards vaccination, perceived severity and perceived vulnerability regarding HBV infection). Four hundred and thirty-three homosexual men completed the questionnaire. We conducted a linear regression analysis to determine the contribution of social-cognitive variables in explaining intention to be vaccinated. Attitude, social norm and perceived vulnerability were significant predictors of intention. Usually, health education emphasizes the severity of a disease, but from this analysis we can conclude that gay men should be convinced of their personal vulnerability to HBV, the benefits of vaccination, and that important referents of the targeted person think positively about vaccination.