[Meningococcal disease in Spain, 1990-1997. Change in its epidemiological pattern].

Area of Science:

• Epidemiology
• Microbiology
• Public Health

Background:

• Meningococcal disease in Spain historically linked to Neisseria meningitidis serogroup B.
• Shift observed in the early 1990s towards serogroup C strains and increased disease incidence.
• Focus on the epidemiological changes during 1990-1997, particularly serogroup C emergence.

Purpose of the Study:

• Characterize the epidemiological pattern of meningococcal disease in Spain (1990-1997).
• Investigate the role of the C:2b:P1.2,5 phenotype during this period of etiological change.

Main Methods:

• Retrospective study of meningococcal disease cases across Spain (1990-1997).
• Utilized data from the Compulsory Disease Reporting system and the Meningococcus Reference Laboratory.
• Exclusions: Andalusia, Cantabria, Madrid, Basque Country, and Valencia.

Main Results:

• Overall incidence of meningococcal disease was 3.81 per 10^5 person-years, with a yearly increase.
• Serogroup C incidence tripled from 1995, reaching 2 per 10^5 in 1997, driven by the C:2b:P1.2,5 phenotype.
• Increased incidence noted in all age groups, particularly 5-19 year-olds; higher mortality associated with C:2b:P1.2,5 compared to serogroup B.

Conclusions:

• The 1990-1997 period in Spain saw a rise in serogroup C meningococcal disease, notably the C:2b:P1.2,5 phenotype.
• Observed shifts in incidence to older age groups, increased case aggregation, and higher mortality with the new phenotype.
• These patterns are indicative of an epidemic situation driven by serogroup C strains.