Immunization, Vaccines and Biologicals

Meningococcal meningitis

Neisseria meningitidis (meningococcus) is a leading cause of bacterial meningitis and septicaemia. Endemic disease occurs worldwide, with outbreaks most frequently occurring in the “meningitis belt” of sub-Saharan Africa. There are no reliable estimates of global meningococcal disease burden due to inadequate surveillance in several parts of the world. Invasive meningococcal disease has a very high fatality rate (>50% if untreated) and many survivors develop permanent sequelae. Of the 12 N. meningitidis serogroups identified, A, B, C, X, W, and Y are responsible for the majority of disease, but serogroup distribution varies by location and time. Meningococcal infections are transmitted through contact with respiratory droplets or secretions.

Currently there are several polysaccharide and conjugate vaccines available for protection from the most common serogroups of meningococcal disease. Polysaccharide vaccines are available in bivalent (A, C), trivalent (A, C, W135), and quadrivalent (A, C, W135, Y) formulations. Conjugate vaccines, which are more immunogenic and can provide herd protection, are available in monovalent (A or C), quadrivalent (A, C, W135, Y), or combination (serogroup C and Haemophilus influenzae type b) formulations. Two protein-based vaccines are available for immunization against serogroup B invasive disease. There are no vaccines available against serogroup X disease.

In 2010, a new meningococcal A conjugate vaccine (MenAfriVac, Serum Institute of India), developed through the WHO-PATH Meningitis Vaccine Project, was introduced in Africa, and has dramatically reduced the number of cases due to N. meningitidis A in these epidemic-prone areas. MenAfriVac is also the first vaccine to be approved for use in a controlled-temperature chain (CTC), allowing the vaccine to be kept at a broader range of temperatures than the traditional cold chain for a limited period of time under monitored and controlled conditions.

WHO recommends that countries with high (>10 cases per 100,000 population/year) or intermediate (2-10 cases per 100,000 population/year) endemic rates and/or frequent epidemics of invasive meningococcal disease conduct appropriate large scale meningococcal vaccination programmes. The importance of conducting high quality surveillance and vaccination programme evaluation in these countries is also stressed.

In addition, WHO recommends that countries of the African meningitis belt complete their campaigns in individuals aged 1-29 years and introduce 1 dose of meningococcal A conjugate vaccine at 9-18 months of age, into the routine immunization programme within 1-5 years following their mass campaign. A one-time catch-up campaign should also be conducted for birth cohorts born since the initial mass vaccination and who will be outside the target age for the routine dose. In areas where routine coverage is less than 60%, periodic campaigns should be considered. Vaccination of pregnant women with MenAfriVac is safe, as assessed in a well-conducted observational study, and they should be vaccinated if in the age range targeted by the mass vaccination campaigns.

In countries where the disease occurs less frequently (<2 cases per 100,000 population/year), meningococcal vaccination is recommended for defined risk groups. Laboratory worker and travelers at risk of exposure should be vaccinated against the prevalent serogroup(s), and vaccination should be offered to all individuals suffering from immunodeficiency.

WHO position papers

Disease burden and surveillance

Vaccine topics

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Further information

Last updated: 30 April 2015

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