Typhoid Vi Vaccine Effectiveness in Hechi, Guangxi, China
Condition: Typhoid; Paratyphoid Fever
MeSH terms: Typhoid Fever; Paratyphoid Fever
Study type: Interventional
Phase: Phase 4

Summary: 
      This study is part of International Vaccine Institute (IVI)'s typhoid Vi demonstration
      project that aims to accelerate the rational introduction of Vi vaccines in typhoid endemic
      countries. The purpose of this study is to determine the effectiveness of the Vi vaccine
      following a mass typhoid immunization campaign in an endemic area in Hechi City in the
      Guangxhi province of China. The cost-effectiveness and safety of Vi vaccination will also be
      evaluated.
    

Detailed description: 
      Typhoid fever is a major cause of morbidity worldwide. The disease predominantly affects
      school-aged children, is more prevalent in urban areas, may last for several weeks and can
      lead to serious complications. Management of this disease is further complicated by the
      emergence of multi-drug resistant strains. Vaccination of high risk populations is considered
      the most promising strategy for the control of typhoid fever. The Vi polysaccharide vaccine
      has been targeted for accelerated introduction into public health programs due to the
      following reasons: it has been shown to have consistent efficacy results even in areas of
      high typhoid incidence, is given as a single dose, lacks patent protection and requires less
      strict cold chain requirements.

      This project attempts to evaluate a new vaccination strategy for residents of endemic areas.
      A cluster-randomized trial involving the Vi polysaccharide vaccine and an active control
      (meningococcal A vaccine) was designed to determine the effectiveness and the feasibility of
      providing Vi vaccine under actual programmatic conditions in 2 populous townships of Hechi
      City. The vaccines used in this study are locally produced and licensed in China. A 1 year
      pilot phase will precede the actual Vi-demonstration project. Surveillance for typhoid fever
      cases will continue after the mass immunization campaign. A passive surveillance system to
      evaluate adverse events following immunization will be implemented. Socio-economic studies
      will be conducted in parallel to the effectiveness evaluation. The knowledge, attitudes,
      beliefs and practices among parents and health care providers regarding typhoid illness,
      treatment and prevention will be assessed. Logistic, feasibility and vaccine costs will also
      be determined.

      Secondary objectives of this trial are:

        -  To estimate the logistic feasibility of a mass typhoid immunization campaign

        -  To assess the knowledge, attitudes, beliefs and practices among parents and health care
           providers regarding typhoid illness, treatment and prevention

        -  To study typhoid fever risk factors in the population
    

Intervention name(s): Typhoid Vi vaccine; Meningococcal A (control)
Intervention type(s): Biological; Biological
Allocation: Randomized
Intervention model: Single Group Assignment
Masking: Double
Primary purpose: Prevention
Keywords: salmonella; typhoid vaccine; enteric fever