Immunization, Vaccines and Biologicals


Typhoid fever is caused by Salmonella typhi, the typhoid bacillus. It is characterized by the sudden onset of sustained fever, severe headache, nausea, loss of appetite, constipation or sometimes diarrhoea. Severe forms have been described with mental dullness and meningitis. Case-fatality rates of 10% can be reduced to less than 1% with appropriate antibiotic therapy. However, strains resistant to chloramphenicol and other recommended antibiotics (ampicillin, cotrimoxazole and even ciprofloxacin) have become prevalent in several areas of the world. Paratyphoid fever can be caused by any of three serotypes of S. paratyphi A, B and C. It is similar in its symptoms to typhoid fever, but tends to be milder, with a lower fatality rate. More

WHO position papers

Further Information

Last updated: 25 January 2008