Human challenge studies using wild-type viruses replicate what is seen in the field in the same populations, and as such they have been used to aid vaccine and drug development for decades. Viral load and symptom reduction are typical key endpoints for direct acting antivirals. However, more recently immunomodulators have been developed that treat the disease processes and they look to establish mechanism of action in a human infection, with a focus on achieving reduction of both symptoms and disease biomarkers. Defining relevant endpoints can be important in establishing confidence of mechanism of action of immunomodulators in infected humans.
