Predicted Strain Coverage of a New Meningococcal Multicomponent Vaccine 4CMenB in Spain: Analysis of the Differences with Other European CountriesReportar como inadecuado




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Background

A novel meningococcal multicomponent vaccine, 4CMenB Bexsero®, has been approved in Europe, Canada, Australia and US. The potential impact of 4CMenB on strain coverage is being estimated by using Meningococcal Antigen Typing System MATS, an ELISA assay which measures vaccine antigen expression and diversity in each strain. Here we show the genetic characterization and the 4CMenB potential coverage of Spanish invasive strains collected during one epidemiological year compared to other European countries and discuss the potential reasons for the lower estimate of coverage in Spain.

Material and Methods

A panel of 300 strains, a representative sample of all serogroup B Neisseria meningitidis notified cases in Spain from 2009 to 2010, was characterized by multilocus sequence typing MLST and FetA variable region determination. 4CMenB vaccine antigens, PorA, factor H binding protein fHbp, Neisseria Heparin Binding Antigen NHBA and Neisserial adhesin A NadA were molecularly typed by sequencing. PorA coverage was assigned to strain with VR2 = 4. The levels of expression and cross-reactivity of fHbp, NHBA and NadA were analyzed using MATS ELISA.

Findings

Global estimated strain coverage by MATS was 68.67% 95% CI: 47.77–84.59%, with 51.33%, 15.33% and 2% of strains covered by one, two and three vaccine antigens, respectively. The predicted strain coverage by individual antigens was: 42% NHBA, 36.33% fHbp, 8.33% PorA and 1.33% NadA. Coverage within the most prevalent clonal complexes cc was 70.37% for cc 269, 30.19% for cc 213 and 95.83% for cc 32.

Conclusions

Clonal complexes cc distribution accounts for variations in strain coverage, so that country-by-country investigations of strain coverage and cc prevalence are important. Because the cc distribution could also vary over time, which in turn could lead to changes in strain coverage, continuous detailed surveillance and monitoring of vaccine antigens expression is needed in those countries where the multicomponent vaccine is introduced. This is really important in countries like Spain where most of the strains are predicted to be covered by only one vaccine antigen and the chance for escape mutants to emerge with vaccine use is higher. Based on the observed data, cc213 should receive special attention as it is associated with low predicted strain coverage, and has recently emerged in Spain.



Autor: Raquel Abad , Verónica Medina, Maria Stella, Giuseppe Boccadifuoco, Maurizio Comanducci, Stefania Bambini, Alessandro Muzzi, Jul

Fuente: http://plos.srce.hr/



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