Epidemiology of the Meningococcal Disease in Catalonia before and after Vaccination against Serogroup C

Backgrounds: Meningococcal disease remains a serious public health problem worldwide. In Catalonia, after implementing the vaccination program, there has been a significant decrease in cases caused by meningococcus C. Methods: Reported cases of meningococcal disease between 1997 and 2008 were analyzed to determine the evolution after the introduction of a conjugated vaccine in Catalonia. Results: In <6 years, the incidence rate of serogroup C fell front 7.6 to 0.6 per 100,000 persons/year in the periods before (1997-2000) and after (2001-2007) the introduction of the conjugate vaccine. In serogroup B, the reduction was from 15.4 to 11.1 In <20 years case-fatality-rate increased only in serogroup B (3% and 7.4%). Serosubtype P1.15 was the most frequent in serogroup B (31%), mainly associated with serotype 4 (80%), and in serogroup C subtype P1.5 (36%), with serotype 2a (86%). During 2008, 5 apparently unrelated cases of B:2a:P1.5 were identified in the same geographic area, with a case-fatality-rate of 80%. Conclusions: Exhaustive surveillance of circulating meningococcal strains is essential.