Het Rijksvaccinatieprogramma in Nederland : Surveillance en ontwikkelingen in 2014-2015

In Nederland is de vaccinatiegraad binnen het Rijksvaccinatieprogramma (RVP) hoog, waardoor weinig mensen de ziekten krijgen waartegen zij worden ingeënt. Alleen de deelname aan de vaccinatie van meisjes tegen het humaan papillomavirus (HPV) ligt lager. Na de vaccinaties komen weinig ernstige bijwerkingen voor. Bijwerkingen die gerapporteerd worden zijn doorgaans niet ernstig van aard zijn. Continue monitoring is nodig om een optimaal vaccinatieprogramma te behouden. Wijzigingen in het vaccinatieschema in 2014-2015 Sinds januari 2014 is de vaccinatie tegen het HPV-virus, dat baarmoederhalskanker kan veroorzaken, teruggebracht naar twee prikken. De vaccinatie wordt aan alle twaalfjarige meisjes aangeboden. Ontwikkelingen voor RVP-ziekten Door de uitbreiding van het pneumokokkenvaccin met drie typen in 2011 is het aantal kinderen gedaald dat van deze drie typen ziek werd. Deze daling was ook te zien onder volwassenen, die mogelijk indirect door de vaccinatie van kinderen zijn beschermd.Kinkhoest nam in 2014 weer toe na een daling in 2013. Het aantal zieken was minder hoog dan tijdens de epidemie in 2012. De bof kwam weinig voor in 2014, al steeg het aantal meldingen weer in de eerste maanden van 2015. De meeste mazelengevallen zijn in de eerste twee maanden van 2014 gerapporteerd, aan het einde van de epidemie die in 2013 begon. De mazelen kwam voor in gebieden waar mensen zich om religieuze redenen vaak niet laten vaccineren. Er zijn geen gevallen van polio gemeld. Vorig jaar waren de controles op polio geïntensiveerd in regio's in Nederland waar vluchtelingen worden opgevangen. Dit betrof vluchtelingen uit enkele niet-Europese landen waar het aantal poliogevallen was gestegen, zoals Syrië. Aangezien polio in die landen in 2014 minder voorkwam zijn de controles tot een normaal niveau teruggebracht. Ontwikkelingen voor toekomstige RVP-kandidaten De Gezondheidsraad kan de minister adviseren om het aantal ziekten die onder het RVP vallen uit te breiden. Het RIVM houdt in de gaten hoe ziekten die hiervoor in aanmerking komen, zich ontwikkelen. In 2014 kwamen uitzonderlijk weinig infecties met het rotavirus voor. Ook daalde het aantal zieken door meningokokken serogroep B. Het aantal mensen met het waterpokken, gordelroos en hepatitis A is de afgelopen jaren stabiel gebleven.In the Netherlands, participation in the National Immunisation Programme (NIP) is high, resulting in low incidences of most diseases included in the NIP. Yet coverage for vaccination against human papillomavirus (HPV) in girls is lower. Only a few severe adverse events following immunisation occurred. Reported adverse events are mostly mild and transient. Continuous monitoring of effectiveness and safety is necessary for the programme to remain optimal. Changes in the vaccination schedule in 2014-2015 Since 2014, girls have been receiving a reduced number of doses against human papillomavirus (HPV). Two doses of HPV vaccine are offered to 12-year-old girls. Developments for diseases included in the NIP The switch to the 10-valent pneumococcal vaccine (PCV10) in 2011 reduced the number of invasive pneumococcal diseases caused by the additional PCV10 serotypes in the vaccinated age groups. A decrease in the incidence of IPD caused by the additional PCV10 serotypes was also seen in the adult age groups, which is probably due to indirect protection. The incidence of pertussis increased in 2014 after a lower incidence in 2013, but was somewhat lower than during the epidemic year 2012. The incidence of mumps was low in 2014, but a resurgence of mumps and an endemic transmission were encountered in the first few months of 2015. The majority of the measles cases reported in 2014 belonged to the measles epidemic in the Bible Belt, which started in 2013. No cases of polio were reported. The environmental routine surveillance, which was intensified in the region where refugees were first cared for in 2013, was changed to routine level again in April 2015. Developments for future NIP candidates The Health Council could advise the Dutch Minister of Health, Welfare and Sports on expansion of the NIP. The National Institute for Public Health and the Environment in the Netherlands (RIVM) investigates developments in potential future NIP candidates. In 2014, the rotavirus season was exceptionally low. A decrease in meningococcal serogroup B disease was seen in 2014. Incidences of varicella zoster virus and hepatitis A remained stable over the previous years.Ministerie van VW

Seroepidemiology of diphtheria, tetanus, poliomyelitis and pertussis : evaluation of the national immunisation programme in the Netherlands

In view of the evaluation of the National Immunisation Programme in the Netherlands the main objectives were to obtain insight into the immunity to diphtheria, tetanus and poliomyelitis, into the occurrence of pertussis and to improve serodiagnosis of pertussis.In a population-based nationwide sampling, 8359 sera (response 55%) were collected, and to gain access to orthodox reformed individuals refusing vaccination, in a sample from municipalities with low vaccine coverage 1589 sera (response 52.5%). In the nationwide sample, the prevalence of diphtheria and tetanus antibodies (≥0.01 IU/ml in toxin inhibition assay) was 88% and 84%, resp. In at least 90% antibodies (titre≥1:8 in neutralisation assay) against poliovirus types 1, 2 and 3 were measured. For those born after mass vaccination was introduced (&lt;45 years) the prevalence of antibodies to diphtheria, tetanus, poliovirus types 1 and 2 was at least 92.5% and for poliovirus type 3 at least 80%. Diphtheria and tetanus antibodies decreased with age for those born before vaccination was introduced (≥45 years). Only 40% of orthodox reformed individuals had diphtheria and 60% had tetanus antibodies. Less than 70% had poliovirus type 1, 2 and/or 3 antibodies. We concluded that the Dutch immunisation programme induced long-term diphtheria, tetanus and poliomyelitis immunity. While adults are very well protected against poliomyelitis, a great number of adults lack diphtheria or tetanus antitoxin antibodies. These adults might benefit from diphtheria (re)vaccination; however, offering a primary tetanus vaccination to cohorts born before the introduction of vaccination would probably be more effective than routine revaccination. Introduction of C. diphtheriae or poliovirus in socio-geographically clustered orthodox reformed groups might constitute a danger of spread of these pathogens.Pertussis surveillance data from notifications, positive serology and hospital admissions (1976-98) showed a sudden increase in the number of pertussis cases in 1996-97. According to notifications and serology data, the increase among, mostly unvaccinated, children less than 1 year was similar to the increase in hospital admissions. For older, mostly vaccinated, individuals the increase in hospital admissions was relatively small. The increase of reported vaccinated patients of all ages was higher than for unvaccinated patients. We postulated that the proportion of pertussis infections resulting in recognizable symptoms has increased among vaccinated individuals due to a mismatch of the vaccine strain and circulating B. pertussis strains.To investigate at which level IgG antibodies against pertussis toxin (IgG-PT) in a single serum sample are indicative for recent pertussis, IgG-PT was analysed in 7756 population-based sera, in sera of 3491 patients with at least a fourfold IgG-PT increase, in paired sera of 89 patients with positive cultures or polymerase chain reactions and in sera of 57 pertussis patients with a median follow-up of 1.4 years. IgG-PT levels of at least 100 U/ml were present in less than 1% of the population, are reached by most pertussis patients within 4 weeks after disease onset and persist only temporarily. We concluded that such levels are diagnostic for recent or actual infection with B. pertussis .Our results not only show that childhood vaccination should be sustained, but that adult vaccination could be considered. We have to anticipate long-term effects of mass vaccination, such as gaps in immunity as a result of decreased circulation of the pathogens and waning immunity. Epidemiological studies directed towards evaluation of vaccination should continue to provide a scientific basis for vaccination strategy.</p

Attitudes of Dutch general practitioners towards vaccinating the elderly:less is more?

Background: In many European countries, vaccinations are offered to the elderly. Expanding the programme to include routine vaccination against pneumococcal disease, herpes zoster, and pertussis, for example, could reduce disease burden amongst the growing population of persons aged 50 years and older. Since most countries involve general practitioners (GPs) in the programmes, the potential success of such new vaccinations depends on the attitude of GPs towards these vaccinations. This qualitative study explores Dutch GPs' attitudes regarding vaccination in general, and their attitudes regarding the incorporation of additional vaccines in the current Dutch influenza vaccination programme. Methods: Interviews were held with ten Dutch GPs (five men and five women) that worked either in an academic hospital, in a practice based in a health center, or in individual practice. All interviews were recorded with a digital voice recorder and transcribed verbatim. Transcripts were analysed according to thematic analysis. Results: GPs perceived prevention as part as their job and believed vaccination to be effective for preventing infectious diseases. However, influenza vaccination was not always perceived as effective. Doubts regarding the usefulness of additional vaccinations were identified. If additional vaccines would be offered, this should be based on scientific evidence and the severity of the infectious disease. Selection of patients for vaccination should not be based solely on age, but more on risk factors. The GP should be the central point of contact for new vaccination campaigns; however, high workload was seen as a concern. Several GPs questioned their ability to refuse to distribute the vaccinations. Conclusions: A positive attitude towards implementing additional vaccinations is not apparent. Achieving the most health benefits seems to be the most important consideration of Dutch GPs regarding vaccinating older adults. Questions regarding the usefulness of vaccinating older adults should be taken into consideration. More research is necessary to confirm the results among a wider range of Dutch GPs

Effects of fear and attention on human balance control

A fall is one of the main causes of injury-related hospitalisation and injury-related deaths. Besides physical degeneration, fear of falling and attentional focus strategies are related to fall risk and decline of balance performance. The aim of this research was to expose the mechanisms by which fear of falling and attentional focus affect human balance control. We used galvanic vestibular stimulation (GVS) to induce vestibular balance reflexes while participants stood at ground level and on a narrow walkway at 3.85 m height to induce fear of falling. Using questionnaires and skin conductance measurements, a fear of falling at height was confirmed. Full-body kinematics was collected to measure the vestibular balance response. We concluded that fear modifies vestibular balance control and proposed a mechanism in which both the short- and medium-latency reflexes functionally contribute to whole body balance. Furthermore, the literature suggests that fear of falling could impair balance mechanisms in elderly through changes in attentional focus. Therefore, we also investigated the effect of attentional focus (internal vs. external focus and reinvestment) and fall history on walking stability in healthy older adults. Participants’ gait was perturbed through randomly occurring unilateral treadmill decelerations to evoke balance recovery movements. Using full body kinematics, coefficients of variation of spatiotemporal gait parameters and local divergence exponents were calculated to assess gait performance of balance recovery responses and unperturbed gait. Fallers showed increased gait variability and decreased gait stability, however no effects of attentional focus were found. The benefits of an external focus of attention on motor performance do not seem to apply to gait in elderly. Continued investigation into attentional focus effects and fear of falling on gait including holistic and partial internal focus and continuous gait perturbations, might further clarify the relations between fear of falling and attentional focus and how they could affect fall risk. Follow-up studies with clinical subgroups could further clarify the relation between fear of falling, attentional focus and balance performance

Het Rijksvaccinatieprogramma in Nederland. Surveillance en ontwikkelingen in 2021-2022

RIVM tracks how many people fall ill due to a disease that is included in the National Immunisation Programme (NIP). In 2021, fewer people got such a disease compared to 2020. This is very likely due to COVID-19 control measures such as social distancing and handwashing. There were especially fewer people with invasive pneumococcal disease (about 1,205 people), pertussis (74), and mumps (1). The number of notifications for meningococcal disease caused by serotype W (4) decreased further, after introduction of the vaccine for adolescents into the NIP in 2020. There were no notifications of diphtheria, tetanus, measles, rubella, or polio in 2021. The number of chronic hepatitis B notifications (743) was about the same as in 2020. Between 2014 and 2019 there were many more notifications, with about 1,000 to 1,100 people being made aware they had this disease. The decrease is probably the result of a decrease in doctors’ visits and therefore diagnoses during the COVID-19 pandemic. Only Haemophilus influenzae type b (Hib) occurred more frequently than before the COVID-19 pandemic. In 2020 and 2021 there were 68 notifications per year, compared to 39 in 2019. RIVM currently investigates the cause. The vaccine seems to be as effective as in previous years. In 2021, 1,703,102 children were vaccinated as part of the NIP. They received a total of 2,219,341 vaccinations. Also, 115,886 pregnant women received a vaccination that protects their baby immediately after birth against, amongst others, whooping cough. Vaccination coverage in the Netherlands is slightly lower than last year. This is partly because of the COVID-19 pandemic, which caused some vaccinations to be given later than normally planned. The Health Council of the Netherlands recommended in June 2021 to offer rotavirus vaccination to young babies. In September 2021, the Health Council recommended inviting more risk groups for flu vaccination, including pregnant women. The ministry of Health, Welfare and Sport adopted both recommendations in 2022. Vaccination against COVID-19 works well to prevent severe illness and death, but the protection slowly decreases. Booster vaccinations increase protection again.Het RIVM houdt elk jaar bij hoeveel mensen een ziekte krijgen waartegen vanuit het Rijksvaccinatieprogramma (RVP) wordt gevaccineerd. In 2021 kregen minder mensen zo’n ziekte dan in 2020. Dit komt waarschijnlijk door de coronamaatregelen, zoals afstand houden en handen wassen. Er waren vooral minder mensen met invasieve pneumokokkenziekte (ongeveer 1.250 personen), kinkhoest (74) en bof (1). Ook is het aantal meningokokkenziekte type W ziektegevallen (4) verder gedaald nadat deze vaccinatie in 2020 voor tieners is toegevoegd aan het RVP. Er waren in 2021 geen mensen met difterie, tetanus, mazelen, rodehond of polio. Het aantal meldingen van chronische hepatitis B (743) was ongeveer hetzelfde als in 2020. Tussen 2014 en 2019 waren dat er veel meer, toen per jaar zo’n 1.000 tot 1.100 mensen te horen kregen dat ze deze ziekte hebben. De daling komt waarschijnlijk doordat mensen tijdens de coronapandemie minder vaak naar een dokter gingen. Alleen Haemophilus influenza type B (Hib) komt vaker voor dan vóór de coronapandemie. In 2020 en 2021 waren er 68 meldingen per jaar, vergeleken met 39 in 2019. Het RIVM onderzoekt de oorzaak. Het vaccin lijkt even effectief te zijn als in eerdere jaren. In 2021 zijn 1.703.102 kinderen gevaccineerd via het RVP. Zij kregen in totaal 2.219.341 vaccinaties. Ook hebben 115.886 zwangere vrouwen een vaccinatie gekregen die hun baby vanaf de geboorte beschermt tegen onder andere kinkhoest. Dit is de 22 wekenprik. De vaccinatiegraad in Nederland is iets lager dan vorig jaar. Dit komt voor een deel door de coronapandemie, waardoor sommige vaccinaties later zijn gegeven dan normaal. De Gezondheidsraad adviseerde in juni 2021 om jonge baby’s tegen het rotavirus te vaccineren. In september 2021 adviseerde de Gezondheidsraad om meer risicogroepen uit te nodigen voor de griepvaccinatie, waaronder zwangere vrouwen. Het ministerie van VWS heeft in 2022 beide adviezen overgenomen. Vaccineren tegen de ziekte COVID-19 werkt goed om ernstige ziekte en sterfte te voorkomen, maar de bescherming neemt langzaam af. De booster- en herhaalvaccinaties zorgen ervoor dat de bescherming weer toeneemt

Estimation of age-specific rates of reactivation and immune boosting of the varicella zoster virus

Studies into the impact of vaccination against the varicella zoster virus (VZV) have increasingly focused on herpes zoster (HZ), which is believed to be increasing in vaccinated populations with decreasing infection pressure. This idea can be traced back to Hope-Simpson's hypothesis, in which a person's immune status determines the likelihood that he/she will develop HZ. Immunity decreases over time, and can be boosted by contact with a person experiencing varicella (exogenous boosting) or by a reactivation attempt of the virus (endogenous boosting). Here we use transmission models to estimate age-specific rates of reactivation and immune boosting, exogenous as well as endogenous, using zoster incidence data from the Netherlands (2002–2011, n = 7026). The boosting and reactivation rates are estimated with splines, enabling these quantities to be optimally informed by the data. The analyses show that models with high levels of exogenous boosting and estimated or zero endogenous boosting, constant rate of loss of immunity, and reactivation rate increasing with age (to more than 5% per year in the elderly) give the best fit to the data. Estimates of the rates of immune boosting and reactivation are strongly correlated. This has important implications as these parameters determine the fraction of the population with waned immunity. We conclude that independent evidence on rates of immune boosting and reactivation in persons with waned immunity are needed to robustly predict the impact of varicella vaccination on the incidence of HZ.PIENTER2 serological stud

Estimating the population-level effectiveness of vaccination program in the Netherlands

BACKGROUND: There are few estimates of the effectiveness of long-standing vaccination programs in developed countries. To fill this gap, we investigate the direct and indirect effectiveness of childhood vaccination programs on mortality at the population level in the Netherlands. METHODS: We focused on three communicable infectious diseases, diphtheria, pertussis, and poliomyelitis, for which we expect both direct and indirect effects. As a negative control, we used tetanus, a non-communicable infectious disease for which only direct effects are anticipated. Mortality data from 1903-2012 were obtained from Statistics Netherlands. Vaccination coverage data were obtained from various official reports. For the birth cohorts 1903 through 1975, all-cause and cause-specific childhood mortality burden was estimated using restricted mean lifetime survival methods, and a model was used to describe the pre-vaccination decline in burden. By projecting model results into the vaccination era, we obtained the expected burden without vaccination. Program effectiveness was estimated as the difference between observed and expected mortality burden. RESULTS: Each vaccination program showed a high overall effectiveness, increasing to nearly 100% within ten birth cohorts. For diphtheria, 14.9% (95% uncertainty interval [UI]: 12.3%, 17.6%) of mortality burden averted by vaccination was due to indirect protection. For pertussis, this was 32.1% (95% UI: 31.3%, 32.8%). No indirect effects were observed for poliomyelitis or tetanus with -2.4% (UI: -16.7%, 7.1%) and 0.6% (UI: -17.9%, 10.7%) respectively. CONCLUSION: Vaccination programs for diphtheria and pertussis showed substantial indirect effects, providing evidence for herd protection

Staat van infectieziekten in Nederland, 2013

In dit rapport wordt gelinked naar een bijlage: appendix150205001.De uitbraak van mazelen in 2013 was de meest in het oog springende infectieziekte van dat jaar. Dit blijkt uit de Staat van Infectieziekten in Nederland 2013, die inzicht geeft in ontwikkelingen van infectieziekten bij de Nederlandse bevolking. Daarnaast worden de ontwikkelingen in het buitenland beschreven die voor Nederland relevant zijn. Met deze jaarlijkse uitgave informeert het RIVM beleidsmakers van het ministerie van Volksgezondheid, Welzijn en Sport (VWS). Elk jaar komt in de Staat van Infectieziekten een thema aan bod; dit jaar is dat de hoeveelheid jaren in goede gezondheid die verloren gaan (ziektelast) door infectieziekten. Sommige infectieziekten, zoals maag-darminfecties, komen erg vaak voor maar veroorzaken over het algemeen geen ernstige klachten. Andere daarentegen, bijvoorbeeld tetanus, komen slechts zelden voor maar veroorzaken relatief veel sterfgevallen. Een gezondheidsmaat die deze aspecten van ziekten combineert is de Disability Adjusted Life Year (DALY). Voor 32 infectieziekten is de ziektelast in Nederland tussen 2007 en 2011 geschat. De gemiddelde jaarlijkse ziektelast voor de totale Nederlandse bevolking was het hoogst voor ernstige pneumokokkenziekte (9444 DALY's per jaar) en griep (8670 DALY's per jaar), die respectievelijk 16 en 15 procent van de totale ziektelast van alle 32 infectieziekten vertegenwoordigen. Na polio en difterie (0 gevallen in de onderzochte periode), werd de laagste ziektelast geschat voor rodehond op 0,14 DALY's per jaar. De ziektelast voor deze ziekten is zo laag dankzij het Rijksvaccinatieprogramma. De ziektelast per individu varieerde van 0,2 DALY's per honderd infecties voor giardiasis (diarree die wordt veroorzaakt door een parasiet), tot 5081 en 3581 DALY's per honderd infecties voor respectievelijk hondsdolheid en een variant van de ziekte van Creutzfeldt-Jakob. Voor alle ziektelaststudies geldt dat de resultaten afhankelijk zijn van de modelparameters en aannames, en van de beschikbaarheid van accurate gegevens over de mate waarin de ziekten voorkomen. Toch kunnen deze schattingen informatief zijn voor beleidsmakers binnen de gezondheidszorg om prioriteiten te kunnen aanbrengen in preventieve en andere maatregelen.The measles outbreak in 2013 was the most striking infectious disease of that year. This is demonstrated in the State of Infectious Diseases in the Netherlands 2013, which provides insight into infectious disease trends in the Dutch population. Developments in other countries that are relevant for the Netherlands are also described. This annual RIVM publication informs policy-makers from the Ministry of Health, Welfare and Sport (VWS). Every year the State of Infectious Diseases in the Netherlands publishes reports on a particular theme. This year's topic concerns the estimation of disease burden: how many years of health life are lost due to infectious diseases? Some infectious diseases, such as gastrointestinal infections, occur frequently in the population, but do not generally give rise to serious complaints. In contrast, other diseases, for example tetanus, occur rarely but may lead to a high risk of death. A summary measure of population health that combines the morbidity and premature mortality attributable to a disease in a single quantity is the Disability Adjusted Life Year (DALY). For 32 infectious diseases, we estimated the disease burden in the Netherlands between 2007 and2011. The highest average annual burden for the total Netherlands population was estimated for invasive pneumococcal disease (9444 DALYs per year) and influenza (8670 DALYs per year), which represent 16 and 15 percent, respectively, of the total burden of all 32 diseases considered. After poliomyelitis and diphtheria (no cases in the period investigated), the lowest burden was estimated for rubella, at 0.14 DALYs per year. The extremely low burden for these diseases is due to the National Immunization Programme. The disease burden per individual varied from 0.2 DALYs per 100 infections for giardiasis (diarrhea that is caused by a parasite), to 5081 and 3581 DALYs per 100 infections for rabies and variant Creutzfeldt-Jakob disease, respectively. As with all burden of disease studies, results depend on disease model parameters and assumptions and on the availability of accurate data on the incidence of infection. Nevertheless, estimates of disease burden can be informative for public health policy-makers regarding the prioritization of preventive and other measures.Ministerie van VW