[Vaccines inf the prevention of fecal hazards]

In addition to the imperative improvement of hygiene standards, vaccines can also be used for the prevention of diseases transmitted by the feco-oral route. Vaccination is essential to protect against poliomyelitis, the eradication of which is targeted through vaccination campaigns using the live, attenuated vaccine in countries where the disease is still endemic and the inactivated vaccine or a combination of both vaccines (mixed schedule) in countries where the disease is under control. The introduction of a specific routine vaccination program against hepatitis A in endemic countries is now starting to be considered. Travellers to these countries must be protected. Among bacterial diseases, only typhoid fever can be prevented by means of an effective vaccine. The difficulties encountered in improving hygiene standards in numerous countries have prompted the WHO to encourage search for new vaccines for the prevention of the diseases transmitted by the feco-oral route. A vaccine against rotavirus that has just been licensed in the USA should permit the global reduction of a significant number of deaths attributable to these viruses. Vaccine prospects for the prevention of hepatitis E are more distant. Several vaccines against Shigella (injectable polysaccharide conjugate vaccine or oral, live, attenuated vaccines obtained by construction of mutant strains) and enterogenic Escherichia coli (oral, inactivated vaccine containing several strains of ETEC and sub-unit B of the cholera toxin), not to mention candidate vaccines against cholera.