Obstacles in measles elimination: an in-depth description of a measles outbreak in Ghent, Belgium, spring 2011

BACKGROUND: From Mid-February to April 2011 one of the largest measles-outbreak in Flanders, since the start of the 2-dose vaccination scheme in 1995, took place in Ghent, Belgium. The outbreak started in a day care center, infecting children too young to be vaccinated, after which it spread to anthroposophic schools with a low measles, mumps and rubella vaccination coverage. This report describes the outbreak and evaluates the control measures and interventions. METHODS: Data collection was done through the system of mandatory notification of the public health authority. Vaccination coverage in the schools was assessed by a questionnaire and the electronic immunization database ‘Vaccinnet’. A case was defined as anyone with laboratory confirmed measles or with clinical symptoms and an epidemiological link to a laboratory confirmed case. Towards the end of the outbreak we only sought laboratory confirmation for persons with an atypical clinical presentation or without an epidemiological link. In search for an index patient we determined the measles IgG level of infants from the day care center. RESULTS: A total of 65 cases were reported of which 31 were laboratory confirmed. Twenty-five were confirmed by PCR and/or IgM. In 6 infants, too young to be vaccinated, only elevated measles IgG levels were found. Most cases (72%) were young children (0–9 years old). All but two cases were completely unimmunized. In the day care center all the infants who were too young to be vaccinated (N=14) were included as cases. Thirteen of them were laboratory confirmed. Eight of these infants were hospitalized with symptoms suspicious for measles. Vaccination coverage in the affected anthroposophic schools was low, 45-49% of the pupils were unvaccinated. We organized vaccination campaigns in the schools and vaccinated 79 persons (25% of those unvaccinated or incompletely vaccinated). CONCLUSIONS: Clustering of unvaccinated persons, in a day care center and in anthroposophic schools, allows for measles outbreaks and is an important obstacle for the elimination of measles. Isolation measures, a vacation period and an immunization campaign limited the spread of measles within the schools but could not prevent further spread among unvaccinated family members. It was necessary to raise clinicians' awareness of measles since it had become a rare, less known disease and went undiagnosed

Clinical burden of hepatitis E virus infection in a tertiary care center in Flanders, Belgium

Background: Hepatitis E virus (HEV) infection is increasingly recognized as a cause of hepatitis in developed countries. A high HEV IgG seroprevalence in humans and pigs is reported as well as sporadic clinical cases of autochtonous HEV but there are currently no data available on the clinical burden of HEV in Belgium. Objectives: The objective of the current study was to evaluate the actual clinical burden of HEV infections in our tertiary care center in Flanders, Belgium. Study design: In the setting of Ghent University Hospital, patients were assessed for the presence of HEV IgG and IgM as well as HEV RNA if no other cause was found for one of the following clinical presentations: a) elevation of liver enzymes in post-liver transplant; b) suspicion of acute or toxic hepatitis; c) unexplainable elevation of liver enzymes; d) cirrhosis with acute-on-chronic exacerbation. Results: In a period of 39 months (January 2011-April 2014) 71 patients were enrolled. HEV IgG was found positive in 13 (18,3%) patients; HEV IgM in 6 patients (8,5%) and HEV RNA in 4 (5,6%) patients. All HEV IgM/ RNA positive patients were male, aged 41-63, and classified in the clinical groups a), b) or d). HEV IgG seroprevalence was slightly higher but not significantly different from the seroprevalence in the general population in this region in Belgium previously reported to be 14% (p-value 0.41) by our group. Conclusions: HEV should be considered as a cause of liver pathology especially in middle-aged men with elevation of liver enzymes

Differences in antigenic sites and other functional regions between genotype A and G mumps virus surface proteins

The surface proteins of the mumps virus, the fusion protein (F) and haemagglutinin-neuraminidase (HN), are key factors in mumps pathogenesis and are important targets for the immune response during mumps virus infection. We compared the predicted amino acid sequences of the F and HN genes from Dutch mumps virus samples from the pre-vaccine era (1957–1982) with mumps virus genotype G strains (from 2004 onwards). Genotype G is the most frequently detected mumps genotype in recent outbreaks in vaccinated communities, especially in Western Europe, the USA and Japan. Amino acid differences between the Jeryl Lynn vaccine strains (genotype A) and genotype G strains were predominantly located in known B-cell epitopes and in N-linked glycosylation sites on the HN protein. There were eight variable amino acid positions specific to genotype A or genotype G sequences in five known B-cell epitopes of the HN protein. These differences may account for the reported antigenic differences between Jeryl Lynn and genotype G strains. We also found amino acid differences in and near sites on the HN protein that have been reported to play a role in mumps virus pathogenesis. These differences may contribute to the occurrence of genotype G outbreaks in vaccinated communities

Eliminatie van Mazelen en Rubella in 2010 : halen we de doelstelling ?

Mazelen is één van de meest besmettelijke infectieziekten waarbij tot in 30% van de gevallen complicaties optreden. Het congenitaal rubellasyndroom is een verzamelnaam voor de afwijkingen die kunnen optreden bij een kind waarvan de moeder tijdens de zwangerschap besmet werd met rubella. Het Regionaal Bureau voor Europa van de Wereldgezondheidsorganisatie gaf in 2010 prioriteit aan de eliminatie van mazelen en het congenitaal rubellasyndroom. Dit artikel beschrijft de belangrijkste klinische en diagnostische aspecten van mazelen en van het congenitaal rubellasyndroom. Vervolgens wordt een overzicht gegeven van de surveillance van mazelen en rubella in België. Hieruit blijkt dat ook in 2009 er nog verschillende gevallen van mazelen voorkwamen. De eliminatiedoelstelling kan bereikt worden maar vraagt een blijvende inspanning van alle gezondheidswerkers

Mazelenepidemie in België. Stand van zaken januari to midden mei 2011.

In België werd tussen 1 januari en 15 mei 2011 melding gemaakt van minstens 231 gevallen van mazelen, terwijl er in het jaar 2010 slechts sprake was van 40 gevallen. Van de 142 gevallen waarvan de vaccinatiestatus gekend was, waren 119 (84%) gevallen niet gevaccineerd. Deze toename in 2011 kan verklaard worden door het nog altijd bestaan van subgroepen met een lage vaccinatiegraad en door de onvoldoende hoge vaccinatiegraad met het mazelen-bof-rubellavaccin in het verleden, waardoor een accumulatie van vatbare personen mogelijk werd. In meerdere Europese landen worden gelijkaardige uitbraken vastgesteld in 2010 en 2011. Naar aanleiding van de Europese vaccinatieweek van 23-30 april 2011 ondernam de Vlaamse Gemeenschap verscheidene sensibilisatieacties. Vanuit het Comité voor de Eliminatie van Mazelen en Rubella gebeurde er een actieve communicatie naar de ziekenhuizen en naar het algemene publiek