Current status of cerebrospinal meningitis and impact of the 2015 meningococcal C vaccination in Kebbi, Northwest Nigeria.

Introduction: Following the significant reduction of Neisseria meningitidis A (NmA) in most parts of northern Nigeria, a new strain of Neisseria meningitidis C (NmC) emerged in 2013 causing outbreaks in the north and recently spreading to southern parts of the Nigeria. This study provides detailed epidemiological investigation in the last four years.
Methods: Analysis of confirmed and suspected cases of meningitis in Kebbi, Nigeria from 2014 to June 2017 detected through Integrated Disease Surveillance and Response.
Results: Of the 2776 cases, 1568 were males, and 1208 females. The median age of males and females was 10 and 11 years (Interquartile range of ages is 9 years) respectively. The attack rate (AR) per 100,000 in the state between 2014 and 2017 was 13.2, 46.7, 2.2 and 3.2 respectively. Case fatality rate (CFR) in 2014 was highest in the 4 years analysed at 13.8%. Binary logistic regression analysis suggests that the odds of confirmation of meningitis was 3.6 (Odds ratio, OR 3.60, 95% CI 1.58-8.2; p = 0.002) times as high in the age group 6-10 years and 2.4 times in the age group 11-19 years compared to the age group 0-5 years (OR 2.44, 95% CI 1.09-5.48; p = 0.03). An epidemic of NmC in 2015, led to a reactive vaccination campaign in selected wards in Aliero and Jega targeting age groups 1-29 years old, with a coverage of 72% and 51% respectively. In 2016-2017 Aliero and Jega local government areas (LGA) had no recorded deaths due to meningitis, a significant improvement over 2015 mortality rates (MR) per 100,000 of 33.4 and 12.2 respectively.
Conclusion: The CFR in the state is still very high, suggesting the need for a more coordinated approach aimed at improving disease notification and early treatment. Vaccination in Aliero and Jega LGAs have demonstrated the usefulness of meningococcal C vaccine in reduction of morbidity and mortality.
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