[Meningococcal disease. The situation in Spain in the 1998-1999 period]

The change in the epidemiological pattern undergone by meningococcal disease in a large part of the country in the 1996-1997 season and the decision to intervene by means of a mass vaccination campaign in the age group between 18 months and 19 years of age, using a bivalent polysaccharide vaccine, justified to enhance the epidemiological surveillance of this disease.

Rates and other indicators of incidence and mortality were calculated for the 1998-1999 campaign by serogroup and age, according to the data notified to the Compulsory Disease Reporting System.

The overall incidence was higher than the previous season, although, the rate ratio did not indicate a significantly greater risk. A statistically significant increase in the rate of incidence caused by serogroup B was registered, and for the second consecutive year, the serogroup C rate dropped, although not significantly. There was an increase in the number of deaths. The fatality rate due to serogroup C increased in the group between 1 and 4 years of age. The incidence remained high and with a clear seasonal pattern in the Communities that did not vaccinate. In the remainder, the incidence dropped and the seasonal pattern disappeared.

Two years after the campaign, the predominance of serogroup B cases is generalised in all of the Autonomous Communities, except in the three where the immunisation was not performed. In the latter, in the course of the last two years, serogroup C has predominated. In the Communities where the vaccination campaign was carried out, there is an increase in the incidence, although not significantly, among children under 4 years of age.