A publication of the Centre for Advancing Journalism, University of Melbourne


Humanity’s deadliest infectious disease is airborne, rampant and not what you think

While the world has been consumed with the fight against a new foe, COVID-19, another ancient airborne infectious killer was quietly gaining strength. Although tuberculosis is today largely forgotten in wealthy countries, the disease continues to shatter lives. Jerome Des Preaux reports.

Humanity’s deadliest infectious disease is airborne, rampant and not what you think

A woman undergoing TB treatment in Daru, Papua New Guinea, takes care of her infant daughter. Photo: PHILIPPE SCHNEIDER/WORLD VISION.

Story by Jerome Des Preaux

Sitting on stage recently at Melbourne’s Doherty Institute for Infection and Immunity, Chris* recalled his experiences being diagnosed with – and surviving – the world’s deadliest infectious disease.

“I had an incredibly bad cough,” Chris recalled. “I couldn’t breathe … I was struggling every day to, basically, live.”

In a post-pandemic world these symptoms sound all too familiar. Only Chris didn’t have COVID.

In 2022, Chris – a 30-something teacher – became one of the 400 to 500 Victorians who are diagnosed every year with tuberculosis (or TB, as it is often known), according to the federal Department of Health and Aged Care’s most recent figures. Worse, he had multi drug-resistant tuberculosis (MDR-TB), which doesn’t respond to the standard regime of antibiotics, requiring months of intensive treatment.

Tuberculosis is not common in Victoria, which has among the lowest rates in the world. Some Australians may recall cases in their family history two or three generations back, but as in most of the wealthy world, tuberculosis is a largely forgotten disease. Chris said that until his diagnosis, he had “no particular idea what it was”.

But in poorer communities throughout the world, tuberculosis has remained widespread. In 2015, with 10 million people a year contracting the disease, the World Health Organisation launched a global campaign to eradicate it by 2035. Through programs targeting awareness, detection, diagnosis and treatment, there had been a steady decrease of nearly 2% per year – until COVID came along. The most recent WHO figures show that while the world was consumed with responding to the COVID-19 pandemic, global deaths from tuberculosis were quietly increasing.

The WHO reported that in 2021 an estimated 10.6 million people became ill with tuberculosis, resulting in 1.6 million deaths worldwide. This was 500,000 cases, and 100,000 deaths, more than 2020, and was the first time in two decades that numbers had risen.

For the TB researchers, physicians, community workers and other specialists listening to Chris’s story at the Doherty Institute on 24 March, World Tuberculosis Day, the disease’s resurgence during the COVID pandemic is a shattering development. Many have been part of the TB eradication effort – researchers, physicians, epidemiologists and community workers who have contributed to programs to build awareness, detect, diagnose and treat TB.

Today, their dream of eradicating TB by 2035 remains a “distant ambition”, said Professor Justin Denholm, medical director of the Victorian Tuberculosis Program.

Among those who have worked for years on the TB strategy was Professor Helen Evans of the Nossal Institute for Global Health, a veteran international vaccine specialist who advises the Australian Government and The Global Fund. She blamed the resurgence of TB on its invisibility in the wealthy world. A “disease of poverty”, it had failed to get much representation or priority at a political level.

Tuberculosis disproportionately affects “overcrowd[ed], marginalised, mobile populations” in developing nations, said Evans. Bangladesh, China, the Democratic Republic of the Congo, India, Indonesia, Pakistan, Philippines and Nigeria account for more than two thirds of cases. Papua New Guinea, Australia’s closest neighbour, has among the highest rates of TB in the world, with 30,000 new cases diagnosed each year.

The disease is also prevalent in Vietnam, where Chris had spent two years teaching, and where he suspects he picked it up. Tuberculosis kills around 14,000 people per year in Vietnam, twice as many as die in traffic accidents, according to the World Health Organisation (WHO).

Invited to speak about the survivor experience on a panel discussing person-centred care, Chris told the World TB Day gathering that he had previously been diagnosed with cancer and Graves’ disease. When he became unwell after returning to Australia from Vietnam due to the pandemic, his initial fear was that his cancer had returned. So when he found out the cancer hadn’t returned, and that it was tuberculosis, “I was incredibly relieved. Until I started doing some research”.

He became deeply concerned that he may have spread it to his family and friends, and that he’d become the “patient zero of a tuberculosis outbreak in Australia”. The bacteria that causes the disease, Mycobacterium tuberculosis, is airborne and easily spread. It usually affects the lungs, and when infected people cough or sneeze the bacteria releases into the air where it can be inhaled.

The ancient pathogen dates back more than 70,000 years, and has been associated with high mortality rates in human populations over centuries. It is today once again the greatest infectious killer of humanity. In recent memory its toll was surpassed by HIV-AIDS from 1999 to 2014, and then by COVID-19 in 2020 and 2021. But while better treatments eased both those outbreaks, tuberculosis endured.

A report in The New England Journal of Medicine said the COVID-19 pandemic was “devastating” for tuberculosis services, even when compared to the effects suffered by the health sector generally. In 2020, strained health services in the countries most affected by tuberculosis were overwhelmed, resulting in only 5.8 million of the 10.1 million cases estimated by the WHO to be reported.

This meant that millions went without adequate treatment, and led to increased transmission of the disease, from people who may not have even known that they had it.

Even in Australia, where cases remained relatively low, there was a spike in tuberculosis diagnoses during the pandemic, a study in the European Respiratory Journal found.

Infectious disease epidemiologist David Dowdy told The Lancet Microbe that the WHO’s 2022 global tuberculosis report is “a stark reminder that tuberculosis is now killing nearly twice as many people as COVID-19 every day”.

Despite the medical community possessing the means to effectively identify and treat the disease, “the major challenge to ending tuberculosis is a lack of global political will to mobilise resources”, said Dowdy.

In Australia, rates of tuberculosis infection are four to five times higher among Aboriginal people than for the non-Indigenous population, according to the federal Department of Health and Aged Care. These heightened rates of tuberculosis are in line with the gaps in health and life expectancy between Indigenous and non-Indigenous Australians, which have been widely acknowledged  through the Close the Gap campaign.

There are indications of some progress, with the national data reporting  a 38% reduction in tuberculosis rates among Aboriginal and Torres Strait Islander Australians between 2015 and 2020.

But tuberculosis in Indigenous communities is not a thing of the past. On 3 March an outbreak was declared on the Anangu Pitjantjatjara Yankunytjatjara (APY) Lands in South Australia, after 10 cases were diagnosed, primarily affecting the Pukatja, Amata, and Pipalyatjara Aboriginal communities.

The APY Lands are remote, with relatively little access to the healthcare necessary to prevent and treat tuberculosis. Treatment protocols for tuberculosis in Australia generally require a course of daily antibiotics for at least six months for drug sensitive TB, longer for drug resistant TB. In response to the APY Lands outbreak, SA Tuberculosis Services Clinical Director Dr Simone Barry met with leaders from the affected communities and said that a portable chest X-ray unit was being used to screen in remote communities.

*In participating in the Doherty Institute discussion, Chris requested not to be fully identified. 

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