A large group of researchers from Canada has developed a new tuberculosis vaccine based on a genetically modified cold virus.
This colorized scanning electron micrograph shows Mycobacterium tuberculosis, gram-positive bacteria that cause tuberculosis. Image credit: Ray Butler / Centers for Disease Control and Prevention.
“We are the first to have developed such a vaccine for tuberculosis,” said Prof Fiona Smaill from McMaster University in Hamilton, Canada, who is a lead author of a paper published in the journal Science Translational Medicine.
“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.”
The new vaccine, based on a recombinant human type 5 adenovirus, was developed to act as a booster to Bacille Calmette Guerin (BCG).
BCG, currently the only tuberculosis vaccine available, was developed in the 1920s and has been used worldwide. The new vaccine would reactivate immune elements that over time diminish following BCG vaccination.
The new vaccine has been more than a decade in the making. The researchers began the first human clinical trial in 2009 with 24 healthy human volunteers, including 12 who were previously BCG-immunized.
“The primary goal was to look at the safety of a single dose vaccine injection, as well as its potency to engage the immune system,” said senior author Prof Zhou Xing from the McMaster Immunology Research Center.
By 2012 the team 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,” Prof Xing said.
“As a doctor who looks after patients who have tuberculosis, including those who are HIV infected, I realize how important it is going to be to control this infection with a good vaccine,” Prof Smaill added.
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Bibliographic information: Smaill F. et al. 2013. A Human Type 5 Adenovirus–Based Tuberculosis Vaccine Induces Robust T Cell Responses in Humans Despite Preexisting Anti-Adenovirus Immunity. Sci. Transl. Med. 5, 205ra134; doi: 10.1126/scitranslmed.3006843
