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Groningen, Netherlands

Bruins M.J.,Laboratory of Clinical Microbiology and Infectious Diseases | Wolfhagen M.J.H.M.,Laboratory of Clinical Microbiology and Infectious Diseases | Schirm J.,Laboratory for Infectious Diseases | Ruijs G.J.H.M.,Laboratory of Clinical Microbiology and Infectious Diseases
European Journal of Clinical Microbiology and Infectious Diseases | Year: 2010

Worldwide noroviruses are an important cause of gastroenteritis and are major agents of both sporadic as well as epidemic infection. Because of the rapid transmission of the virus, early detection is essential. Until recently, the available test methods for the detection in stool were enzyme immunoassays and real-time reverse transcription polymerase chain reaction (RT-PCR), both of which take several hours to perform. We evaluated the rapid immunochromatographic test RIDA®QUICK Norovirus for the detection of norovirus in the stool of patients with acute gastroenteritis. This test is easy to perform and read and only takes 20 min. The sensitivity and specificity compared to RT-PCR results and the positive and negative predictive values were 57.1%, 99.1%, 93.3% and 91.2%, respectively. The rapid test is useful for quick screening, but a negative result should be followed up by RT-PCR. © 2010 Springer-Verlag. Source

de Greeff S.C.,National Institute for Public Health and the Environment | de Melker H.E.,National Institute for Public Health and the Environment | van Gageldonk P.G.M.,National Institute for Public Health and the Environment | Schellekens J.F.P.,Laboratory for Infectious Diseases | And 4 more authors.
PLoS ONE | Year: 2010

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 latter age-categories may limit the effectiveness of pediatric vaccination. © 2010 de Greeff et al. Source

Van Assen S.,University of Groningen | Holvast A.,University of Groningen | Benne C.A.,Laboratory for Infectious Diseases | Posthumus M.D.,University of Groningen | And 8 more authors.
Arthritis and Rheumatism | Year: 2010

Objective. For patients with rheumatoid arthritis (RA), yearly influenza vaccination is recommended. However, its efficacy in patients treated with rituximab is unknown. The objectives of this study were to investigate the efficacy of influenza vaccination in RA patients treated with rituximab and to investigate the duration of the possible suppression of the humoral immune response following rituximab treatment. We also undertook to assess the safety of influenza vaccination and the effects of previous influenza vaccination. Methods. Trivalent influenza subunit vaccine was administered to 23 RA patients who had received rituximab (4-8 weeks after rituximab for 11 patients [the early rituximab subgroup] and 6-10 months after rituximab for 12 patients [the late rituximab subgroup]), 20 RA patients receiving methotrexate (MTX), and 29 healthy controls. Levels of antibodies against the 3 vaccine strains were measured before and 28 days after vaccination using hemagglutination inhibition assay. The Disease Activity Score in 28 joints (DAS28) was used to assess RA activity. Results. Following vaccination, geometric mean titers (GMTs) of antiinfluenza antibodies significantly increased for all influenza strains in the MTX-treated group and in healthy controls, but for no strains in the rituximab-treated group. However, in the late rituximab subgroup, a rise in GMT for the A/H3N2 and A/H1N1 strains was demonstrated, in the absence of a repopulation of CD19+ cells at the time of vaccination. Seroconversion and seroprotection occurred less often in the rituximab-treated group than in the MTX-treated group for the A/H3N2 and A/H1N1 strains, while seroprotection occurred less often in the rituximab-treated group than in the healthy controls for the A/H1N1 strain. Compared with unvaccinated patients in the rituximab-treated group, previously vaccinated patients in the rituximab-treated group had higher pre- and postvaccination GMTs for the A/H1N1 strain. The DAS28 did not change after vaccination. Conclusion. Rituximab reduces humoral responses following influenza vaccination in RA patients, with a modestly restored response 6-10 months after rituximab administration. Previous influenza vaccination in rituximab-treated patients increases pre- and postvaccination titers. RA activity was not influenced. © 2010, American College of Rheumatology. Source

De Greeff S.C.,National Institute for Public Health and the Environment | Mooi F.R.,National Institute for Public Health and the Environment | Westerhof A.,National Institute for Public Health and the Environment | Verbakel J.M.M.,Laboratory for Medical Microbiology and Immunology | And 6 more authors.
Clinical Infectious Diseases | Year: 2010

Background. We conducted a population-based, nation-wide, prospective study to identify who introduced pertussis into the household of infants aged ≤S6 months admitted to the hospital for pertussis in the Netherlands. Methods. During the period 2006-2008, a total of 560 household contacts of 164 hospitalized infants were tested by polymerase chain reaction, culture, and serological examination to establish Bordetella pertussis infection. Clinical symptoms and vaccination history were obtained by a questionnaire submitted during sample collection and 4-6 weeks afterwards. Results. Overall, 299 household contacts (53%) had laboratory-confirmed pertussis; 159 (53%) had symptoms compatible with typical pertussis infection, and 42 (14%) had no symptoms. Among children vaccinated with a whole-cell vaccine, 17 (46%) of 37 had typical pertussis 1-3 years after completion of the primary series, compared with 9 (29%) of 31 children who had been completely vaccinated with an acellular vaccine. For 96 households (60%), the most likely source of infection of the infant was established, being a sibling (41%), mother (38%), or father (17%). Conclusions. If immunity to pertussis in parents is maintained or boosted, 35%-55% of infant, cases could be prevented. Furthermore, we found that, 1-3 years after vaccination with whole-cell or acellular vaccine, a significant percentage of children are again susceptible for typical pertussis. In the long term, pertussis vaccines and vaccination strategies should be improved to provide longer protection and prevent transmission. © 2010 by the Infectious Diseases Society of America. All rights reserved. Source

De Greeff S.C.,National Institute for Public Health and the Environment | De Melker H.E.,National Institute for Public Health and the Environment | Westerhof A.,National Institute for Public Health and the Environment | Schellekens J.F.P.,Laboratory for Infectious Diseases | And 2 more authors.
Epidemiology | Year: 2012

BACKGROUND:: Despite >50 years of universal vaccination, pertussis remains the most prevalent vaccine-preventable infectious disease in developed countries. Pertussis is often mild in adults, but can run a severe course in young infants. METHODS:: Data on transmission of pertussis within households were captured in a population-based, nationwide, prospective study performed in the Netherlands between February 2006 and December 2009. We estimated the transmission rates of pertussis with a clinically confirmed infection in 140 households, using stochastic epidemic models. Parameter estimates were used to gauge the effect of vaccinating household members (cocooning) to prevent the infection in young infants. RESULTS:: Overall transmission rates in the household were high. Fathers were less susceptible than other household members (estimated relative susceptibility of fathers = 0.44 [95% confidence interval (CI) = 0.27-0.72]), whereas mothers may be more infectious to their infants than are other household members (estimated relative infectiousness of mothers = 3.9 [95% CI = 0.59-14]). Targeted vaccination of mothers would approximately halve the probability of infants' infection. Vaccination of siblings is less effective in preventing transmission within the household, but may be as effective overall because siblings more often introduce an infection in the household. Vaccination of fathers is expected to be least effective. CONCLUSIONS:: Selective vaccination of persons in households with a young infant may substantially reduce the disease burden of pertussis in infants by reducing transmission within the household. Copyright © 2012 by Lippincott Williams & Wilkins. Source

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