Cerebrospinal meningococcal disease outbreak in Niger (Update: 8 July 2015)

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Disease Outbreak News

From 1 January to 28 June 2015, Niger’s Ministry of Public Health notified WHO of 8500 suspected cases of meningococcal meningitis, including 573 deaths. This is a rapidly growing outbreak with some unprecedented features.

Suspected cases increased very quickly, tripling weekly between 1-15 May 2015, leading to the first large-scale meningitis outbreak caused by Neisseria meningitidis serogroup C to hit any country in Africa’s meningitis belt.

Thirteen districts from the regions of Niger, one of which includes the capital city, have crossed the epidemic threshold. In Niamey, all five districts in the densely populated urban area of more one million people have been affected causing 5267 suspected cases and 260 deaths.

The outbreak peaked in week 19 (4 to 10 May) with 2182 cases including 132 deaths reported. Since then, the outbreak has been on the decline with just 11 cases including two deaths reported in week 26 (22 to 28 June 2015).

Laboratory tests have confirmed the predominance of Neisseria meningitidis (Nm) serogroup C in the affected areas, with Nm serogroup W also being identified in several patient samples. Although serogroup C has been the predominant cause of meningitis in wealthy countries, it has never been of high concern in Africa.

Public health response

Epidemic committee has been activated to manage the outbreak at all the country levels. An international team composed of staff from WHO and the US Centers for Disease Control and Prevention (CDC), have been deployed to support the Ministry of Public Health’s investigation of the outbreak and reinforce the country’s surveillance capacity.

WHO and partners have provided support to the government of Niger for the implementation of mass vaccination campaigns and other emergency control measures. ICG, with financial support of GAVI, approved four vaccination requests and released 468 000 doses of the older polysaccharide vaccine, which protects against the A, C and W serogroups, 488 500 doses of Mencevax against ACWY and 200 000 doses of the newer conjugate vaccine, which protects against serogroups A, C, W, and Y. In addition, Niger’s government has obtained 200 000 doses of polysaccharide ACWY vaccine from the government of Mali.

In addition to the mass campaign immunization, enhanced surveillance, social mobilization and case management have been performed in all affected areas. These combinations of interventions have led to the control of the outbreak. Currently, no district has reached the alert or epidemic threshold.

The main lessons learnt from the management of this outbreak include the need of availability of more vaccines in the stockpile and the solidarity of non-affected countries by providing vaccines to Niger.