1. Controlled Human Infection Models
“A well characterised strain of an infectious agent is administered at a controlled dose and by a specific route to carefully selected adult volunteers”
Ensures exposure to an infective dose of the pathogen
Useful for:
Investigating pathophysiology
Defining immune response
Testing drugs
Testing vaccines
CHIMs have been used to develop vaccines for typhoid, cholera and malaria

3. Reasons for conducting CHIMS in LMICs
Ethical / social reasons for carrying out CHIMS in countries where the disease exists
Volunteers are the ‘natural’ hosts of the disease, differing from HIC volunteers in factors affecting host-pathogen and host-vaccine interactions
Genetics
Previous exposure to the pathogen / other infections
Immune status
Microbiome
Environmental factors

4. Possible issues with conducting CHIMs in LMICs
Need good clinical and laboratory facilities, careful monitoring, and good governance
Inadequate regulatory framework
Factors hampering fully informed consent
Unfamiliarity of RECs with CHIMs
Natural exposure to related pathogens during study
Natural exposure to vectors during study