Vaccine
-
Neisseria meningitidis is an important cause of bacterial meningitis and septicaemia with most disease caused by meningococci bearing serogroups A, B, C, Y and W-135 polysaccharides. Monovalent serogroup C conjugate vaccines have become established in the immunisation programmes in many countries and the first quadrivalent meningococcal vaccine, containing the polysaccharides from 4 of the serogroups A, C, Y and W-135 meningococci conjugated to a protein carrier was licensed in the US in 2005. This vaccine and others in development offer the potential to broaden population protection against meningococcal disease.
-
Epidemic meningitis in Africa remains an important and unresolved public health problem. Bacteriologic and epidemiologic data collected over the past 30 years have consistently established the importance of Group A Neisseria meningitidis as the dominant etiologic agent. The meningococcal Group A capsule is the major virulence factor; it is a polysaccharide comprised of a repeating unit of partly O-acetylated alpha-1,6-linked N-acetylmannosamine phosphate. ⋯ A meningococcal A conjugate vaccine (MenAfriVac) has been developed and tested in Phase II clinical trials in Africa. The vaccine has been shown to be safe and to generate a sustained immunologic response with functional antibody 20 times higher than that seen with polysaccharide vaccine. Widespread use of such a vaccine is likely to generate herd immunity and to put an end to Group A meningococcal epidemics.
-
Oral polio vaccine has reduced the incidence of polio in India and many states have been polio free for a long time while occasional polio cases are occurring in some states. On the other hand more than 96% of polio cases being reported in India are occurring in Uttar Pradesh and Bihar. The current polio scenario indicates that oral polio vaccines cannot eradicate polio from Uttar Pradesh and Bihar because some children from these two states show poor response to OPV. There is an urgent need for re-appraisal of polio eradication strategy.