In a first, Canadian scientists have developed a new 'booster' vaccine, based on a genetically modified cold virus, to fight against the deadly tuberculosis disease.
The new vaccine acts as a booster to Bacille Calmette Guerin (BCG), currently the only TB vaccine available. BCG was developed in the 1920s and has been used worldwide.
The new 'booster' would reactivate immune elements that over time diminish following BCG vaccination.
"We are the first to have developed such a vaccine for tuberculosis," said Dr Fiona Smaill, professor and chair of the Department of Pathology and Molecular Medicine of the Michael G DeGroote School of Medicine at McMaster University.
She led the phase one clinical study of the vaccine published in the journal Science Translational Medicine.
The vaccine was developed in the lab of Zhou Xing, professor of pathology and molecular medicine and the McMaster Immunology Research Centre, who co-led the phase one study.
"Tuberculosis is a serious public health threat. One-third of world's population is infected with the organism that causes tuberculosis, and it remains the top infectious killer of people only secondary to HIV; yet, the current vaccine used to prevent it is ineffective," Smaill said.
Currently the BCG vaccine is part of the World Health Organisation's immunisation programme in Asia, Africa, Eastern Europe and South America, as well as Nunavut, the only Canadian jurisdiction where the BCG vaccine is routinely given because of the high rate of tuberculosis in the territory. It is typically given in the first year of life.
The McMaster vaccine has been more than a decade in the making. Researchers began the first human clinical trial in 2009 with 24 healthy human volunteers, including 12 who were previously BCG-immunised.
"The primary goal was to look at the safety of a single dose vaccine injection," said Xing, "as well as its potency to engage the immune system."
By 2012 they established that the vaccine was safe and observed a robust immune response in most trial participants. More clinical trials are needed to measure the vaccine's real potential, Xing added.
