Canadian researchers begin human flu infection trials to accelerate vaccine development

Canadian investigators have launched a controlled human infection trial that deliberately introduces a weakened H3N2 influenza strain into the nasal passages of consenting volunteers. The first eight participants began in Halifax, with additional volunteers now enrolled in Montreal, bringing the total target to 32 healthy adults aged 18 to 45. Participants receive either a low or high dose of the virus, or a saline placebo, and are kept in specially designed negative-pressure rooms for a minimum of seven days, receiving round-the-clock monitoring, blood tests and nasal swabs, with antivirals ready if needed.

Led by Brian Ward of the MUHC Vaccine Study Centre and Scott Halperin of Dalhousie University’s Center for Vaccinology, the trial seeks to map early immune responses and establish a platform for rapid assessment of future flu vaccines or pandemic candidates. The effort follows decades of similar studies abroad and addresses ethical concerns by ensuring informed consent and compensation for volunteers. Researchers hope the data will enable testing multiple vaccine candidates quickly during a severe influenza outbreak.