Canada should play a leading role in the world’s fight against TB
One-third of the world’s population is believed to be infected with tuberculosis, which kills nearly 5,000 people each day. It’s not just a problem of poor nations; Canada has a TB crisis of its own in the north, where Indigenous populations have a 300 times greater rate of infection than that of other Canadians. In the U.S., the Centers for Disease Control receives reports of 10,000 new cases each year.
In a world first, the United Nations held a general assembly meeting last Wednesday dedicated to the world’s most deadly infectious disease with dozens of health ministers and global leaders in attendance, pledging billions of dollars, transformative programs and increased commitment to reducing the burden of the disease, which can destroy lung, brain and bone tissue. On the same day, a new study was published showing promise for an experimental vaccine.
But it will take more than pledges and jabs to combat the 14,000-year-old bacterium, which is unique to humans and has co-evolved to stay one step ahead of the global health community. Unlike polio, which has essentially been eradicated thanks to global vaccination efforts, and HIV, which has become a chronic disease for people taking antiretrovirals, the incidence of TB has remained on the World Health Organization’s Top 10 list of global killers for decades.
Developing an effective vaccine has proven challenging, detecting the slowgrowing and rapidly adaptable bacterium is difficult, and treatment courses run six to 24 months and require four to six medicines to be taken many times each day.
The most common way to diagnose TB, the Mantoux skin test, was developed in 1882, and only since 2010 has technology existed to replace the slow process of culturing bacteria to confirm a diagnosis using molecular technology. Since the introduction of medicines like rifampin and isoniazid in the 1960s, it has only been in the past few years that new antibiotics have been introduced, but these have yet to be approved for use in Canada. And a promising vaccine, MVA85A, was proven ineffective in 2013 in a devastating blow to tuberculosis researchers, leaving only the 90-year-old, marginally effective BCG vaccine available.
TB is often exacerbated by other common diseases like HIV and diabetes, which can mask its detection and increase its virulence, leaving it hidden while others are infected or leading to a rapid and severe illness that is too often deadly.
Together, these characteristics of TB make it a truly unique pathogen and one of the greatest public health threats on Earth. Yet new epidemics of ebola, pneumonic plague and opioids overwhelm public health circles despite their far lesser impact on human lives.
Despite the glacial pace of progress, solutions are on the horizon. Last week it was revealed in the New England Journal of Medicine that a new vaccine, M72/ AS01E, reduces the risk of latent infection flourishing to active disease with 54 per cent effectiveness. Gene sequencing to identify TB in sputum and body fluids are becoming more and more accurate, while genome sequencing is becoming far more affordable. New medication regimens are being studied to shorten the course of, and improve the effectiveness of, TB treatment using novel drugs that make treatment easier and less risky. And public health techniques to identify and track cases and improve treatment compliance are improving as technologies such as cellphones spread throughout Africa and Asia. Some of the science contributing to these advances is occurring in Ontario, at McMaster University and St. Joseph’s Healthcare.
Still, the greatest impact on the TB burden will stem from addressing poverty, which is undeniably linked to TB, be it in Kampala or Iqaluit. By displaying leadership on the world stage, Canada can promote health equity through global development policy that attempts to strengthen the economies of low-income countries, improving sanitation and standards of living so that TB cannot thrive. Last week, the UN stood alert to the threat of TB; Canada must maintain the sense of urgency and keep pressure on the world. Together, we can beat this formidable bacterium.