Global practices of meningococcal vaccine use and impact on invasive disease

Abstract

A number of countries now include meningococcal vaccines in their routine immunization programs. This review focuses on different approaches to including meningococcal vaccines in country programs across the world and their effect on the burden of invasive meningococcal disease (IMD) as reflected by pre and post-vaccine incidence rates in the last 20 years. Mass campaigns using conjugated meningococcal vaccines have lead to control of serogroup C meningococcal disease in the UK, Canada, Australia, Spain, Belgium, Ireland, and Iceland. Serogroup B disease, predominant in New Zealand, has been dramatically decreased, partly due to the introduction of an outer membrane vesicle (OMV) vaccine. Polysaccharide vaccines were used in high risk people in Saudi Arabia and Syria and in routine immunization in China and Egypt. The highest incidence region of the meningitis belt initiated vaccination with the serogroup A conjugate vaccine in 2010 and catch-up vaccination is ongoing. Overall results of this vaccine introduction are encouraging especially in countries with a moderate to high level of endemic disease. Continued surveillance is required to monitor effectiveness in countries that recently implemented these programs.

<p>Immunoinformatics and Vaccine Development: An Overview</p>

“…These polysaccharide antigens do not generate memory B cells but can induce longlasting humoral immunity even when recall responses are lacking. 26 Vaccine efficacy may be short term 27 if only the B cells are activated.…”

Towards Predicting Protective Vaccine Responses in the Very Young

“…Among them are the unconjugated polysaccharide vaccine (MPSV4), which is licensed for children 2 years and older, and the protein conjugated vaccine [MCV4; contains the same four polysaccharides conjugated to diphtheria toxoid (DT)], which is licensed for infants 9 months and older, or conjugated to DT-crossreactive material (CRM), which is licensed for infants 2 months and older [39]. All these vaccines induce antibodies to the capsule that fix complement and lead to killing of bacteria in vitro in the serum bactericidal activity (SBA); an SBA titer >1:8 is the presumed correlate of protection [39]. Antibody levels have been found to fall rapidly after early infant vaccination with two doses of all meningococcal glycoconjugate vaccines necessitating a booster at 12 months.…”

Genetic Analysis of Neisseria meningitidis Sequence Type 7 Serogroup X Originating from Serogroup A

“…The capsule is an important marker of virulent N. meningitidis, although many capsulated isolates rarely or never cause invasive meningococcal disease (IMD) (1). The main constituent of the capsule, polysaccharide, is also the effective antigen of most licensed N. meningitidis vaccines (2).…”