Age-Related Immunity to Meningococcal Serogroup C Vaccination: An Increase in the Persistence of IgG2 Correlates with a Decrease in the Avidity of IgG

Contains fulltext : 97618.pdf (publisher's version ) (Open Access)Background All children and adolescents between 1 and 19 years of age in The Netherlands received a single meningococcal serogroup C conjugate (MenCC) vaccine in 2002. During follow-up 4–5 years later, the persistence of MenC polysaccharide-specific IgG was found to be dependent on age of vaccination with higher IgG levels in the oldest immunized age categories. Methods and Findings Two cross-sectional population-based serum banks, collected in 1995/1996 and in 2006/2007, were used for this study. We measured MenC polysaccharide-specific IgM, the IgG1 and IgG2 subclasses and determined the avidity of the IgG antibodies. We report that the age-related persistence of IgG after immunization with the MenCC vaccine seemed to result from an increase of IgG2 levels with age, while IgG1 levels remained stable throughout the different age-cohorts. Furthermore, an age-related increase in IgM levels was observed, correlating with the persistence of IgG antibodies with age. It is noteworthy that the increase in IgG2 correlated with a reduced IgG-avidity with age. Conclusion These date indicate that the classical characteristics of a T-cell-dependent antibody response as elicited by protein based vaccines might not be completely applicable when conjugate vaccines are administered to older children and adolescents up to 18 years of age. The response elicited by the MenCC vaccine seemed to be more a mixture of both T cell dependent and T cell independent responses in terms of humoral immunological characteristics

Immunity against Neisseria meningitidis Serogroup C in the Dutch Population before and after Introduction of the Meningococcal C Conjugate Vaccine

Contains fulltext : 88187.pdf (publisher's version ) (Open Access)BACKGROUND: In 2002 a Meningococcal serogroup C (MenC) conjugate vaccine, with tetanus toxoid as carrier protein, was introduced in the Netherlands as a single-dose at 14 months of age. A catch-up campaign was performed targeting all individuals aged 14 months to 18 years. We determined the MenC-specific immunity before and after introduction of the MenC conjugate (MenCC) vaccine. METHODS AND FINDINGS: Two cross-sectional population-based serum banks, collected in 1995/1996 (n = 8539) and in 2006/2007 (n = 6386), were used for this study. The main outcome measurements were the levels of MenC polysaccharide(PS)-specific IgG and serum bactericidal antibodies (SBA) after routine immunization, 4-5 years after catch-up immunization or by natural immunity. There was an increasing persistence of PS-specific IgG and SBA with age in the catch-up immunized cohorts 4-5 years after their MenCC immunization (MenC PS-specific IgG, 0.25 microg/ml (95%CI: 0.19-0.31 microg/ml) at age 6 years, gradually increasing to 2.34 microg/ml,(95%CI: 1.70-3.32 microg/ml) at age 21-22 years). A comparable pattern was found for antibodies against the carrier protein in children immunized above 9 years of age. In case of vaccination before the age of 5 years, PS-specific IgG was rapidly lost. For all age-cohorts together, SBA seroprevalence (> or =8) increased from 19.7% to 43.0% in the pre- and post-MenC introduction eras, respectively. In non-immunized adults the SBA seroprevalence was not significantly different between the pre- and post-MenC introduction periods, whereas PS-specific IgG was significantly lower in the post-MenC vaccination (GMT, age > or =25 years, 0.10 microg/ml) era compared to the pre-vaccination (GMT, age > or =25 years, 0.43 microg/ml) era. CONCLUSION: MenCC vaccination administered above 5 years of age induced high IgG levels compared to natural exposure, increasing with age. In children below 14 months of age and non-immunized cohorts lower IgG levels were observed compared to the pre-vaccination era, whereas functional levels remained similar in adults. Whether the lower IgG poses individuals at increased risk for MenC disease should be carefully monitored. Large-scale introduction of a MenCC vaccine has led to improved protection in adolescents, but in infants a single-dose schedule may not provide sufficient protection on the long-term and therefore a booster-dose early in adolescence should be considered

Towards an integrated approach in surveillance of vector-borne diseases in Europe

Vector borne disease (VBD) emergence is a complex and dynamic process. Interactions between multiple disciplines and responsible health and environmental authorities are often needed for an effective early warning, surveillance and control of vectors and the diseases they transmit. To fully appreciate this complexity, integrated knowledge about the human and the vector population is desirable. In the current paper, important parameters and terms of both public health and medical entomology are defined in order to establish a common language that facilitates collaboration between the two disciplines. Special focus is put on the different VBD contexts with respect to the current presence or absence of the disease, the pathogen and the vector in a given location. Depending on the context, whether a VBD is endemic or not, surveillance activities are required to assess disease burden or threat, respectively. Following a decision for action, surveillance activities continue to assess trends

Physics, Astrophysics and Cosmology with Gravitational Waves

Gravitational wave detectors are already operating at interesting sensitivity levels, and they have an upgrade path that should result in secure detections by 2014. We review the physics of gravitational waves, how they interact with detectors (bars and interferometers), and how these detectors operate. We study the most likely sources of gravitational waves and review the data analysis methods that are used to extract their signals from detector noise. Then we consider the consequences of gravitational wave detections and observations for physics, astrophysics, and cosmology.Comment: 137 pages, 16 figures, Published version <http://www.livingreviews.org/lrr-2009-2

Trends in het voorkomen van voedselallergie voor pinda, melk en ei in Nederland

Tussen 1995 en 2007 is in Nederland het aantal mensen dat allergisch is voor pinda's toegenomen. Voedselallergie voor koemelk en ei is niet toegenomen. Dit blijkt uit onderzoek van het RIVM uitgevoerd in opdracht van de Voedsel en Warenautoriteit (VWA) om trends vast te stellen in de mate waarin voedselallergie in Nederland voorkomt. In het onderzoek is de mate waarin voedselallergie voorkomt gebaseerd op de aanwezigheid van IgE-antistoffen tegen pinda, melk of ei in bloed, een maat voor allergische sensibilisatie. Ongeveer 30 tot 60% van de personen met deze antistoffen heeft daadwerkelijk allergische klachten. In westerse landen zijn in de jaren tachtig en negentig van de vorige eeuw allergische aandoeningen zoals astma en eczeem sterk toegenomen. Enkele studies tonen aan dat voedselallergie voor pinda ook aan het toenemen is. Het is echter nog niet bekend welke genetische en omgevingsfactoren deze toename kunnen verklaren. Pinda-allergie heeft een grote invloed op de kwaliteit van leven. Allergische mensen die per ongeluk pinda's eten kunnen daar levensbedreigende symptomen van ondervinden. Dit kan alleen voorkomen worden door geen pinda's te eten. Dat is niet altijd gemakkelijk omdat pinda's in veel voedingsproducten worden verwerkt. Voor deze studie is de aanwezigheid van IgE-antistoffen tegen de onderzochte voedingsstoffen in bloed bepaald. De bloedmonsters zijn in twee perioden afgenomen, waartussen ongeveer tien jaar tijd zit (1995/1996 en 2006/2007). De mate waarin sensibilisatie voorkomt is voor vier leeftijdscategorieen bepaald: 0 tot 4 jaar, 5 tot 18 jaar, 19 tot 40 jaar en 41 tot 79 jaar.In the Netherlands, the number of people with a peanut allergy increased in the period from 1995 to 2007. There are no indications of any increase in food allergies for cow's milk and eggs. These results were obtained from a study carried out by the National Institute for Public Health and the Environment (RIVM) by order of the Food and Consumer Product Safety Authority. The aim of this research was to investigate whether there are any trends in the prevalence of food allergies in the Netherlands. In this study, the prevalence of food allergy was based on the presence of IgE antibodies specific for peanuts, cow's milk and eggs in human blood - a measure for allergic sensitization. Approximately 30 to 60% of these sensitized subjects will develop allergic symptoms. The prevalence of allergic diseases, such as asthma and eczema has increased in Western countries during the nineteen-eighties and nineties. There are indications that the prevalence of peanut allergy is also increasing. It is currently unknown which genetic and environmental factors are involved in this increase. Peanut allergy has a large impact on a person's quality of life. Allergic people who accidentally ingest peanuts can develop life-threatening symptoms, which can only be prevented by eliminating peanuts from the diet. This is not always easy, since peanuts are used as ingredients in many food products. In this study the presence of IgE antibodies for the food allergens was assessed in blood. The blood samples were obtained in two different time periods: in 1995/1996 and in 2006/2007. The prevalence of sensitization was assessed in four age groups: 0-4 years, 5-18 years, 19-40 years and 41-79 years.VW

Seroprevalence of Pertussis in the Netherlands: Evidence for Increased Circulation of Bordetella pertussis

Background: In many countries, the reported pertussis has increased despite high vaccination coverage. However, accurate determination of the burden of disease is hampered by reporting artifacts. The infection frequency is more reliably estimated on the basis of the prevalence of high IgG concentrations against pertussis toxin (IgG-Ptx). We determined whether the increase in reported pertussis in the last decade is associated with an increase in the number of infections. Methodology/Principal Findings: In a cross-sectional population-based serosurveillance study conducted in 2006-07, from a randomly selected age-stratified sample of 7,903 persons, serum IgG-Ptx concentrations were analyzed using a fluorescent bead-based multiplex immuno assay. In 2006-07, 9.3 % (95%CI 8.5-10.1) of the population above 9 years of age had an IgG-Ptx concentration above 62.5 EU/ml (suggestive for pertussis infection in the past year), which was more than double compared to 1995-96 (4.0%; 95%CI 3.3-4.7). The reported incidence showed a similar increase as the seroprevalence between both periods. Conclusions: Although changes in the vaccination program have reduced pertussis morbidity in childhood, they have not affected the increased infection rate in adolescent and adult pertussis. Indeed, the high circulation of B. pertussis in the latte

Is a single dose of meningococcal serogroup C conjugate vaccine sufficient for protection? experience from the Netherlands

<p>Abstract</p> <p>Background</p> <p>The first meningococcal serogroup C (MenC) conjugate vaccine was licensed in 1999 and introduced in the United Kingdom. Countries that have implemented the MenC vaccine since then in their national immunisation programmes use different schedules. Nevertheless, all involved countries seem to experience substantial declines in the incidence of MenC disease.</p> <p>Discussion</p> <p>Since 2001, the MenC conjugate vaccine has been implemented in the Netherlands by offering a single dose to all children aged 14 months. Prior to the introduction of the vaccine into the national immunisation programme, a catch-up vaccination campaign was initiated in which a single dose of the MenC conjugate vaccine was offered to all children aged from 14 months up to and including 18 years. Since then, there has been no report of any case of MenC disease among immunocompetent vaccinees. Administration of a single dose of MenC conjugate vaccine after infancy could be beneficial considering the already complex immunisation schedules with large numbers of vaccinations in the first year of life. The present paper deals with the advantages and critical aspects of a single dose of the MenC conjugate vaccine.</p> <p>Summary</p> <p>A single dose of MenC conjugate vaccine at the age of 14 months in combination with a catch up vaccine campaign appeared to be a successful strategy to prevent MenC disease in the Netherlands, thereby confirming that a single dose of the vaccine could sufficiently protect against disease. Nevertheless, this approach can only be justified in countries with a relatively low incidence of serogroup C meningococcal disease in the first year of life. Furthermore, a good surveillance programme is recommended for timely detection of vaccine breakthroughs and outbreaks among non-vaccinees, since long-term protection after a single dose in the second year of life cannot currently be guaranteed.</p