No abstract

Typhoid fever remains an important health threat in many parts of the world, with an estimated 16 million cases and 600,000 deaths occurring each year. The emergence of Salmonella typhi strains multiply resistant to antibiotics has complicated the treatment of this disease. Field experience of 8 years shows that a vaccine composed of purified Vi capsular polysaccharide of Salmonella typhi, given as a single intramuscular or deep subcutaneous injection, has consistent immunogenicity and efficacy. Side effects, based on reports since 1989, are infrequent and mild. Furthermore, the Vi vaccine may be administered simultaneously with other common "travel" vaccines, at two different sites of injection, without affecting immunogenicity and tolerability. This review presents an update of the development and clinical experience with the Salmonella typhi Vi polysaccharide vaccine (Typhim Vi; Pasteur Mérieux Connaught, France).

No abstract

The five-component DTaP vaccine may be combined with PRP-T vaccine without clinically significant immunologic interaction when given in a 2-, 4-, 6-, and 18-month schedule.

The control strategy of meningitis epidemics in sub-Saharan countries, although reexamined regularly, is based on epidemiological, immunological and logistical considerations put forward at the end of the 1970s. It comprises organizing large-scale vaccinations in the event of a declared epidemic. The obvious failure of this strategy recommended by the World Health Organization (WHO) necessitates evaluation of the emergency vaccination criteria. Despite current controversy on the immunogenicity of the polysaccharide vaccine, its safety, effectiveness in the field and low cost could justify the reopening of a debate on its use in routine vaccination. Routine--or preventive--vaccination could significantly reduce the incidence of meningococcal meningitis and its severity. The conjugate vaccine, when available, will constitute an additional advantage in the prevention of meningococcal meningitis. A strategy combining both polysaccharide and conjugate vaccines according to the population targets and possibilities for funding remain to be defined.