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.