[Meningococcal C conjugate vaccine: Impact of a vaccination program and long-term effectiveness in Navarra, Spain, 2000-2014].

Background: Since 2000, when the meningococcal serogroupC conjugate vaccine (MenCC) was introduced in the childhood immunization schedule in Spain, several changes in the schedule and catch-up campaigns have been performed. We aim to estimate the impact and effectiveness of this vaccine in Navarra up to 2014.

Methods: The impact of the vaccination program was analysed by comparing incidence, mortality and lethality rates of disease before (1995-1999) and after (2004-2014) the introduction of the MenCC. Vaccine effectiveness was estimated using the screening method (Farrington) and the indirect cohort method (Broome). Data on cases were obtained from the active surveillance of meningococcal disease.

Results: During 1995-1999 the mean annual incidence of meningococcalC disease was 1.32 per 100,000, and 7.18 per 100,000 in children younger than 15years. The fall of meningococcalC disease incidence was significant in cohorts targeted for vaccination from the beginning and progressive in the general population. No cases were reported between 2011 and 2014. The estimated vaccine effectiveness was 96% by the screening method, and 99% by the indirect cohort method.

Conclusion: The MenCC vaccination program has been successful in decreasing the incidence rate of serogroupC meningococcal disease in Navarra, and schedule changes have maintained high vaccine effectiveness throughout the study period.