Introduction
TYPHOID FEVER, SYSTEMIC INFECTION, DISEASES, DISEASE
Typhoid fever, a systemic infection caused by Post-introduction vaccine evaluations are necessary to understand vaccine performance under real-world conditions and to provide information to sustain vaccination programmes and support decision making. Case-control studies offer an efficient approach to estimate vaccine effectiveness, because cases are identified based on disease status (ie, the outcome of interest), and sample size requirements tend to be smaller than for other study designs, especially for diseases with low prevalence.
