Challenge Unit

Learn more about the challenge unit at the challenge unit website at

The Challenge Unit is a state-of-the-art 10-bed inpatient and outpatient research facility located in the IWK Health Centre in Halifax designed to conduct human challenge trials and other specialized clinical trials.

View facility photo tour

Medical Director | Dr. Scott Halperin

Unit Manager |  Kara Redden

Administrator | Ying Watt


Human challenge trials, also known as controlled human infection models, are a type of clinical trial that intentionally exposes healthy, informed, and consenting human volunteers to an infectious virus or bacteria. This is done in a safe environment that prevents the spread of the illness and with healthcare support. Safety and containment are paramount which is why the VCU holds an in-unit nurse’s station, on-call physician’s room, and medication preparation room,  along with other clinical resources limiting the need for staff and samples to leave the unit.

Participants may be either vaccinated to test a vaccine or unvaccinated to help researchers learn more about how an illness spreads and interacts with our immune system inside the body to make us sick.

Modern human challenge trials are held to the highest ethical and safety standards. A human challenge trial may only be considered when the infection being tested comes on quickly, can be easily detected, and has an existing treatment that can be given to prevent significant illness.  Participant welfare is the highest priority and challenge trials are conducted within an ethical framework in which truly informed consent can be given, and in which the risks are comparable to a standard clinical trial.

Research studies and Clinical Trials in Canada that involve human participants in Canada are regulated by Research Ethics Boards such as the Nova Scotia Health Research Ethics Board and IWK Research Ethics Board. Every REB is guided by the principles of the second edition of the Tri-Council Policy Statement:  Ethical Conduct for Research Involving Humans.