Typhoid vaccines.

Typhoid fever continues to be a major public health problem in developing countries with about 33 million cases per year. Protective efficacy of traditional acetone/phenol killed vaccines is similar to newer typhoid vaccines (Ty21A and Vi antigen vaccine) but side effects of these newer vaccines are considerably less. Though the mortality is low, typhoid fever causes considerable morbidity and loss of working days. Problems during treatment are increasing due to emergence and spread of multidrug resistant S. typhi. Hence to decrease the incidence of typhoid fever in addition to ensuring safe water supply and excreta disposal a typhoid vaccine needs to be introduced in the National Immunization Schedule.