Adults' perceived prevalence of enteric fever predicts laboratory-validated incidence of typhoid fever in children.

This study was undertaken to develop a model to predict the incidence of typhoid in children based on adults' perception of prevalence of enteric fever in the wider community. Typhoid cases among children, aged 5-15 years, from epidemic regions in five Asian countries were confirmed with a positive Salmonella Typhi culture of the blood sample. Estimates of the prevalence of enteric fever were obtained from random samples of adults in the same study sites. Regression models were used for establishing the prediction equation. The percentages of enteric fever reported by adults and cases of typhoid incidence per 100,000, detected through blood culture were 4.7 and 24.18 for Viet Nam, 3.8 and 29.20 for China, 26.3 and 180.33 for Indonesia, 66.0 and 454.15 for India, and 52.7 and 407.18 for Pakistan respectively. An established prediction equation was: incidence of typhoid (1/100,000= -2.6946 + 7.2296 x reported prevalence of enteric fever (%) (F=31.7, p<0.01; R2=0.992). Using adults' perception of prevalence of disease as the basis for estimating its incidence in children provides a cost-effective behavioural epidemiologic method to facilitate prevention and control of the disease.

Sociobehavioural research methods for the introduction of vaccines in the Diseases of the Most Impoverished Programme.

Participation in vaccination campaigns worldwide, particularly the Expanded Programme on Immunization, has increased significantly in recent years. However, there remain multiple and integrated behavioural, sociocultural and political-economic barriers to vaccination. The Diseases of the Most Impoverished (DOMI) Programme has undertaken shigellosis disease-burden studies and oral cholera and typhoid Vi polysaccharide vaccine trials in seven Asian countries. As part of these projects, sociobehavioural studies have been undertaken to determine the potential demand for vaccines for these diseases and the obstacles and enabling factors that may affect acceptance, delivery, and use of vaccines. A theoretical model of acceptance of vaccination and a triangulation of qualitative and quantitative methods have been used for fully elucidating the range of issues relating to vaccination for shigellosis, cholera, and typhoid fever. In this paper, the theoretical and methodological basis of the DOMI projects has been reviewed in a context of current sociobehavioural research on the acceptability and desirability of vaccination.