Human trials are set to begin early next year at an Ontario university for two next-generation COVID-19 vaccines that can be inhaled.
Fiona Smaill is a professor of pathology and molecular medicine at McMaster University in Hamilton and lead researcher for the clinical trials. She said on Tuesday that both vaccines, which would be the first inhaled vaccines, are “approved for study in Canada.” They’re designed to combat variants of concern and are delivered by inhaled aerosol, targeting the lungs and upper airways, where respiratory infections begin.
“The novel part of our vaccine is that we’re administering it by inhaled aerosol, and so the immune response that is generated in the lungs,” Smaill told CBC Hamilton.
“Not only do we have the vector that is unique, but we also have the route of administration and the generation of what we call a mucosal immunity, which we believe is a very effective form of immunity against respiratory viruses like COVID.”
Health Canada recently gave the go-ahead for the clinical trials to start, Smaill told CBC News.
WATCH | Prof. Fiona Smaill of McMaster University discuss the new vaccine trials:
The vaccines, which express three different SARS-CoV-2 proteins, including the distinctive spike protein, are designed to also target other parts of the virus that do not change or mutate, Smaill said.
“We believe that by including the three proteins … that we will more likely have a broader immune response that will address some of the challenges with the variants of concern.”
The researcher said they expect to start enrolling participants within the next two weeks, and begin administering the vaccine in the new year.
“We’re looking for healthy volunteers who have had two doses of an mRNA vaccine or the Pfizer or Moderna vaccine — at least the second one three months ago,” Smaill said.
Potential volunteers, who must be healthy, would be between ages 18 and 65, with no underlying health problems or issues with lung function.
Study to include at least 30 healthy volunteers
The researchers said they will examine how the immune response develops in the lungs and blood after vaccination and monitor for possible side-effects.
According to a news release announcing the trials, researchers are comparing two strains of weakened adenovirus as platforms for the vaccines: one is made with a human adenovirus, the other is a chimpanzee adenovirus.
“In their natural form, adenoviruses cause respiratory infections such as the common cold, and in rare cases can cause a lung infection such as pneumonia. In their weakened form, they do not spread disease, but can be customized to serve as vehicles, or vectors, to trigger targeted immune responses,” the news release said.
Smaill said the human adenovirus “has been well characterized as a viral vector,” while the chimpanzee adenovirus is used by AstraZeneca and J&J in their COVID-19 vaccines.
“We’ve got these two different adenovirus vectors that we then inserted the genes for the three proteins — the spike protein, as well as the polymerase protein and a nuclear protein,” she told CBC News.
At least 30 healthy volunteers will take part in the study, which is being funded by the Canadian Institutes for Health Research.
Smaill said if Phase 1 is successful, the team has manufactured sufficient vaccine doses to move forward with much larger clinical trials, which could potentially lead to broader use.
“Assuming that we see no safety signals and we are comfortable with the dose that’s been chosen, we would then enrol a large number of individuals in a Phase 2 study, managing the study design depending on how things evolve with the goal of getting support to be able to roll this type of technology out to a wider population,” Smaill told CBC News.
Matthew Miller, an associate professor with McMaster’s Michael G. DeGroote Institute for Infectious Disease Research and co-principal investigator, said the university has a long history studying adenoviruses.
“This human trial builds on that pioneering work, and in addition to addressing an issue of tremendous public health importance, will also advance our fundamental understanding of how to use these viruses most effectively as vaccine vectors.”