Browsing by Author "Tzanakaki, Georgina"
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- Genetic Meningococcal Antigen Typing System (gMATS): A genotyping tool that predicts 4CMenB strain coverage worldwidePublication . Muzzi, Alessandro; Brozzi, Alessandro; Serino, Laura; Bodini, Margherita; Abad, Raquel; Caugant, Dominique; Comanducci, Maurizio; Lemos, Ana Paula; Gorla, Maria Cecilia; Křížová, Pavla; Mikula, Claudia; Mulhall, Robert; Nissen, Michael; Nohynek, Hanna; Simões, Maria João; Skoczyńska, Anna; Stefanelli, Paola; Taha, Muhamed-Kheir; Toropainen, Maija; Tzanakaki, Georgina; Vadivelu-Pechai, Kumaran; Watson, Philip; Vazquez, Julio A.; Rajam, Gowrisankar; Rappuoli, Rino; Borrow, Ray; Medini, DuccioBackground: The Meningococcal Antigen Typing System (MATS) was developed to identify meningococcus group B strains with a high likelihood of being covered by the 4CMenB vaccine, but is limited by the requirement for viable isolates from culture-confirmed cases. We examined if antigen genotyping could complement MATS in predicting strain coverage by the 4CMenB vaccine. Methods: From a panel of 3912 MATS-typed invasive meningococcal disease isolates collected in England and Wales in 2007-2008, 2014-2015 and 2015-2016, and in 16 other countries in 2000-2015, 3481 isolates were also characterized by antigen genotyping. Individual associations between antigen genotypes and MATS coverage for each 4CMenB component were used to define a genetic MATS (gMATS). gMATS estimates were compared with England and Wales human complement serum bactericidal assay (hSBA) data and vaccine effectiveness (VE) data from England. Results: Overall, 81% of the strain panel had genetically predictable MATS coverage, with 92% accuracy and highly concordant results across national panels (Lin's accuracy coefficient, 0.98; root-mean-square deviation, 6%). England and Wales strain coverage estimates were 72-73% by genotyping (66-73% by MATS), underestimating hSBA values after four vaccine doses (88%) and VE after two doses (83%). The gMATS predicted strain coverage in other countries was 58-88%. Conclusions: gMATS can replace MATS in predicting 4CMenB strain coverage in four out of five cases, without requiring a cultivable isolate, and is open to further improvement. Both methods underestimated VE in England. Strain coverage predictions in other countries matched or exceeded England and Wales estimates.
- Implications of differential age distribution of disease-associated meningococcal lineages for vaccine developmentPublication . Brehony, Carina; Trotter, Caroline L.; Ramsay, Mary E.; Jolley, Keith A.; van der Ende, Arie; Carion, Françoise; Berthelsen, Lene; Hoffmann, Steen; Harðardóttir, Hjördís; Vazquez, Julio A.; Murphy, Karen; Toropainen, Maija; Caniça, Manuela; Ferreira, Eugenia; Diggle, Mathew; Edwards, Giles F; Taha, Muhamed-Kheir; Stefanelli, Paola; Kriz, Paula; Gray, Steve J.; Fox, Andrew J.; Jacobsson, Susanne; Claus, Heike; Vogel, Ulrich; Tzanakaki, Georgina; Heuberger, Sigrid; Caugant, Dominique A.; Frosch, Matthias; Maiden, Martin C. J.New vaccines targeting meningococci expressing serogroup B polysaccharide have been developed, with some being licensed in Europe. Coverage depends on the distribution of disease-associated genotypes, which may vary by age. It is well established that a small number of hyperinvasive lineages account for most disease, and these lineages are associated with particular antigens, including vaccine candidates. A collection of 4,048 representative meningococcal disease isolates from 18 European countries, collected over a 3-year period, were characterized by multilocus sequence typing (MLST). Age data were available for 3,147 isolates. The proportions of hyperinvasive lineages, identified as particular clonal complexes (ccs) by MLST, differed among age groups. Subjects <1 year of age experienced lower risk of sequence type 11 (ST-11) cc, ST-32 cc, and ST-269 cc disease and higher risk of disease due to unassigned STs, 1- to 4-year-olds experienced lower risk of ST-11 cc and ST-32 cc disease, 5- to 14-year-olds were less likely to experience ST-11 cc and ST-269 cc disease, and ≥25-year-olds were more likely to experience disease due to less common ccs and unassigned STs. Younger and older subjects were vulnerable to a more diverse set of genotypes, indicating the more clonal nature of genotypes affecting adolescents and young adults. Knowledge of temporal and spatial diversity and the dynamics of meningococcal populations is essential for disease control by vaccines, as coverage is lineage specific. The nonrandom age distribution of hyperinvasive lineages has consequences for the design and implementation of vaccines, as different variants, or perhaps targets, may be required for different age groups.
- Increase of invasive meningococcal serogroup W disease in Europe, 2013 to 2017Publication . Krone, Manuel; Gray, Steve; Abad, Raquel; Skoczyńska, Anna; Stefanelli, Paola; van der Ende, Arie; Tzanakaki, Georgina; Mölling, Paula; João Simões, Maria; Křížová, Pavla; Emonet, Stéphane; Caugant, Dominique A.; Toropainen, Maija; Vazquez, Julio; Waśko, Izabela; Knol, Mirjam J.; Jacobsson, Susanne; Rodrigues Bettencourt, Célia; Musilek, Martin; Born, Rita; Vogel, Ulrich; Borrow, RayBackground: The total incidence of invasive meningococcal disease (IMD) in Europe has been declining in recent years; however, a rising incidence due to serogroup W (MenW), predominantly sequence type 11 (ST-11), clonal complex 11 (cc11), was reported in some European countries. Aim: The aim of this study was to compile the most recent laboratory surveillance data on MenW IMD from several European countries to assess recent trends in Europe. Methods: In this observational, retrospective study, IMD surveillance data collected from 2013–17 by national reference laboratories and surveillance units from 13 European countries were analysed using descriptive statistics. Results: The overall incidence of IMD has been stable during the study period. Incidence of MenW IMD per 100,000 population (2013: 0.03; 2014: 0.05; 2015: 0.08; 2016: 0.11; 2017: 0.11) and the proportion of this serogroup among all invasive cases (2013: 5% (116/2,216); 2014: 9% (161/1,761); 2015: 13% (271/2,074); 2016: 17% (388/2,222); 2017: 19% (393/2,112)) continuously increased. The most affected countries were England, the Netherlands, Switzerland and Sweden. MenW was more frequent in older age groups (≥ 45 years), while the proportion in children (< 15 years) was lower than in other age groups. Of the culture-confirmed MenW IMD cases, 80% (615/767) were caused by hypervirulent cc11. Conclusion: During the years 2013–17, an increase in MenW IMD, mainly caused by MenW cc11, was observed in the majority of European countries. Given the unpredictable nature of meningococcal spread and the epidemiological potential of cc11, European countries may consider preventive strategies adapted to their contexts.
- Meningococcal serogroup Y disease in Europe: Continuation of high importance in some European regions in 2013Publication . Bröker, Michael; Emonet, Stéphane; Fazio, Cecilia; Jacobsson, Susanne; Koliou, Maria; Kuusi, Markku; Pace, David; Paragi, Metka; Pysik, Alexander; Simões, Maria João; Skoczynska, Anna; Stefanelli, Paola; Toropainen, Maija; Taha, Muhamed Kheir; Tzanakaki, GeorginaNeisseria meningitidis or meningococcus is divided into 12 distinct serogroups of which A, B, C, W, X, and Y are medically most important and cause health problems in different parts of the world. The epidemiology of N. meningitidis is unpredictable over time and across geographic regions. Globally, serogoup A has been prevalent in the African “meningitis belt” whereas serogroup B and C have predominated in Europe. In a paper published earlier in this journal1, an increase in serogroup Y invasive meningococcal disease (IMD) in some European countries was reported based on the epidemiological data for 2010, 2011 and 2012. Here, we report additional data from 30 European countries indicating that high or increased serogroup Y disease levels have continued in 2013 in certain regions of Europe. In the Western and Central Europe, there were no major changes in the proportion of serogroup Y IMD cases in 2013 compared to 2012. In the Scandinavian countries, proportion of serogroup Y disease remained high, ranging from 26% to 51% in 2013. This was in contrast to Baltic, Eastern and most Southern European countries, where the proportion of serogroup Y IMD was low similarly to previous years. For the last 2 decades, the mean age of patients affected by serogroup Y was 41 y for 7 countries from which data was available and 50% of cases were in patients aged 45 to 88 y. The age distribution of serogroup Y was bimodal and did not change significantly despite the increase of the total number and the proportion of serogroup Y IMD in some European regions.