Abstract
There are only 10 contemporary, population-based studies of typhoid fever that
evaluate disease incidence using blood culture for confirmation of cases.
Reported incidence ranged from 13 to 976/100 000 persons per year.
These studies are likely to have been done preferentially in high- incidence
sites which makes generalization of data difficult. Only five of these studies
reported mortality. Of these the median (range) mortality
was 0%
(0–1·8%). Since study
conditions usually involved enhanced clinical management of patients and the
studies were not designed to evaluate mortality as an outcome, their usefulness
for generalizing case-fatality rates is uncertain. No contemporary
population-based studies reported rates of complications. Hospital-based typhoid
fever studies reported median (range) complication rates
of 2·8%
(0·6–4·9%) for
intestinal perforation and case-fatality rates of 2·0%
(0–14·8%). Rates of
complications other than intestinal perforation were not reported in
contemporary hospital-based studies. Hospital-based studies capture information
on the most severe illnesses among persons who have access to health-care
services limiting their generalizability. Only two studies have informed the
current understanding of typhoid fever age distribution curves. Extrapolation
from population-based studies suggests that most typhoid fever occurs among
young children in Asia. To reduce gaps in the current understanding of typhoid
fever incidence, complications, and case-fatality rate, large population-based
studies using blood culture confirmation of cases are needed in representative
sites, especially in low and medium human development index countries outside
Asia.