The importance of generating evidence on typhoid fever for implementing vaccination strategies

Duncan Steele

doi:10.3855/jidc.217

Abstract

Typhoid fever, caused by Salmonella enterica serovar Typhi (S. Typhi), remains a major cause of enteric disease and a significant public health problem, predominantly in children in developing countries. Global estimates of typhoid fever range from 17 to 22 million cases per year with an associated 216,000 to 600,000 deaths annually [1,2]. This lower estimate is based on a conservative case fatality rate of 1%, (CRF range varies from 1% to 4%); yet the number of typhoidrelated deaths each year is comparable to that of other diseases that are considered top priorities for disease control in the global health community, including cervical cancer caused by HPV, and is greater than others such as Japanese encephalitis and meningococcal meningitis. The continued high burden of typhoid fever and the alarming spread of antibiotic resistant strains led the World Health Organization (WHO), almost ten years ago, to recommend immunization using the two new-generation vaccines in schoolaged children in areas where typhoid fever posed a significant problem and where antibiotic resistant strains were prevalent [3]. Nevertheless, with the exception of certain provinces in China, parts of Vietnam and one state in India, this recommendation has yet to be implemented in typhoid-endemic countries. Several reasons have been given for this lack

Highlights

Typhoid fever, caused by Salmonella enterica serovar Typhi
There has been a sense of complacency created by the introduction of relatively inexpensive antibiotics several decades ago, which were effective in substantially reducing typhoid-related deaths, but which have progressively become ineffective due to the acquisition of antibiotic resistance by the bacterium
New data from Asia on the disease and economic burden of typhoid fever, recent trends in antibiotic resistance, and vaccine effectiveness and cost-effectiveness, along with the increased availability of typhoid vaccines and sharp reductions in their price, led World Health Organization (WHO) to review, update and reinforce its recommendations for the use of typhoid vaccines for populations at high risk, so that this disease can truly be controlled in countries where it remains a significant public health problem [5]

Summary

Introduction

Typhi), remains a major cause of enteric disease and a significant public health problem, predominantly in children in developing countries. The continued high burden of typhoid fever and the alarming spread of antibiotic resistant strains led the World Health Organization (WHO), almost ten years ago, to recommend immunization using the two new-generation vaccines in schoolaged children in areas where typhoid fever posed a significant problem and where antibiotic resistant strains were prevalent [3].

Results

Conclusion