Immunization, Vaccines and Biologicals

Countries with high or intermediate endemic rates of meningococcal disease encouraged to introduce large scale vaccination programmes

Mother and child in Ouagadoudou

In a position paper, published in the Weekly Epidemiological Record today, WHO recommends that countries with high or intermediate endemic rates of meningococcal disease and countries with frequent epidemics introduce large scale vaccination programmes, using meningococcal conjugate vaccines. In these countries, the meningococcal vaccine may be administered through routine immunization programmes and supplementary immunization activities, for example during disease outbreaks.

In countries where meningococcal disease occurs less frequently, vaccination is recommended for defined risk groups such as children and young adults living in closed communities, for instance in boarding schools or military camps. Laboratory workers at risk of exposure to meningococci and travellers to high-endemic areas should also be vaccinated.

For all countries, knowledge of meningococcal disease burden is critical in ensuring that available vaccines are appropriately used. Countries considering the use of meningococcal vaccines should develop the surveillance systems to characterize meningococcal disease epidemiology. And continued surveillance should dictate the need and timing of repeat mass vaccination campaigns.

Meningococcal meningitis is a bacterial form of meningitis, a serious infection of the meninges that affects the brain membrane. It can cause severe brain damage and fatality rates can be as high as 50% of cases if untreated. Several different bacteria can cause meningitis. Neisseria meningitidis is the one with the potential to cause large epidemics. Twelve serogroups of Neisseria meningitidis have been identified, six of which (A, B, C, X, Y and W135) can cause epidemics. Geographic distribution and epidemic capabilities differ according to the serogroup.

In Africa, major epidemics have been occurring over the past 100 years. Most of them have been attributed to serogroup A and occurred in the African "meningitis belt”, a large area that spans sub-Saharan Africa from Senegal in the west to Ethiopia in the east. In 1996 to 1997, the largest epidemic in history swept across the belt, causing over 250 000 cases, an estimated 25 000 deaths, and disability in 50 000 people. Large epidemics recur in the meningitis belt on a regular basis. Meningococcal polysaccharide vaccines used for epidemic response are not appropriate for preventive strategies.

In December 2010, the first meningococcal A conjugate vaccine to be developed specifically for countries in the African meningitis belt was introduced in Burkina Faso, Mali and Niger. Three additional countries ― Cameroon, Chad and Nigeria ― are introducing the vaccine in December 2011.

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